################################################################################ # # # CIF Dictionary for Modulated Structures # # --------------------------------------- # # # # CIF data definitions specifically for Modulated Structures. These are in # # addition to those defined in the CIF Core Dictionary version 2.3 (2003). # # # # The data included in this dictionary are intended to fulfil the Checklist # # for the Description of Incommensurate Modulated Crystal Structures, # # published by the Commission on Aperiodic Crystals. Acta Cryst. (1997), # # A53, 95-100. # # # # The DDL commands used in this dictionary are defined in ddl_core.dic (1.4) # ################################################################################ data_on_this_dictionary _dictionary_name cif_ms.dic _dictionary_version 1.0.1 _dictionary_update 2005-06-16 _dictionary_history ; 1994-09-12 Initial definitions G. Madariaga 1994-09-19 Several corrections I.D. Brown 1994-09-19 Loops with mixed categories removed G. Madariaga 1994-09-20 Addition of W for composites S. van Smaalen 1995-03-21 A new way of labelling parameters G. Madariaga 1995-03-21 Extensive use of _type_construct G. Madariaga 1995-04-05 Does _type_construct allow structured items? G. Madariaga 1995-04-06 New entries G. Madariaga 1995-04-10 Block identifiers added G. Madariaga 1997-05-26 _units_extension, _units_description and _units_conversion substituted by _units and _units_detail G. Madariaga 1997-05-26 Units included in the definitions G. Madariaga 1997-05-26 _symm_ substituted by _symmetry_ G. Madariaga 1997-05-26 category SYMMETRY_EQUIV added G. Madariaga 1997-05-27 explicit definition of _cell_matrix_W_ G. Madariaga 1997-05-27 _cell_matrix_W_organization removed G. Madariaga 1997-05-27 _enumeration_range 1:8 added to _cell_modulation_dimension G. Madariaga 1997-05-27 _enumeration_range 4:11 modified in _cell_reciprocal_basis_vect_numb G. Madariaga 1997-05-27 _diffrn_refln_indices _diffrn_reflns_limit_indices _diffrn_standard_refln_indices _exptl_crystal_face_indices _refln_indices and _reflns_limit_indices_ replaced by _diffrn_refln_extra_index_ _diffrn_reflns_limit_extra_index_ _diffrn_standard_refln_extra_index_ _exptl_crystal_face_extra_index_ _refln_extra_index_ and _diffrn_reflns_limit_extra_index_ G. Madariaga 1997-05-28 _block_id substituted by _audit_block_code, _audit_link_block_code and _audit_link_block_description G. Madariaga 1997-05-28 added _refine_ls_by_class_R_Fsqd_factor and _refine_ls_by_class_R_I_factor G. Madariaga 1997-05-28 added _refine_ls_by_class_d_res_ G. Madariaga 1997-05-29 deleted _refine_ls_Fourier_term and _refine_ls_Fourier_term_code G. Madariaga 1997-06-03 deleted _atom_site_coeff_, _atom_site_Fourier_label_, _atom_site_Fourier_phase_ G. Madariaga 1997-06-03 added the new datanames _atom_site_Fourier_ according to David's suggestions G. Madariaga 1997-07-14 complete revision of _atom_site_Fourier_ items G. Madariaga 1997-07-18 added the new datanames _atom_site_spec_func_disp_label, _atom_site_spec_func_occ_label, _atom_site_spec_func_temp_label G. Madariaga 1997-07-18 *_special_func_ -> *_spec_func_ *_special_par_ -> *_spec_param_ *_special_param_ -> *_spec_param_ G. Madariaga 1997-07-18 deleted *_special_npar_ G. Madariaga 1997-07-18 _atom_site_spec_label_ substituted by _atom_site_spec_param_ added the following parent/child relationships _refine_ls_spec_param_disp_code and _atom_site_spec_param_disp_code, _refine_ls_spec_param_occ_code and _atom_site_spec_param_occ_code, _refine_ls_spec_param_temp_code and _atom_site_spec_param_temp_code G. Madariaga 1997-07-18 redefined _atom_site_phason_label, added _atom_site_phason_formula G. Madariaga 1997-07-21 added _refine_ls_spec_param_rot_ and _atom_site_spec_param_rot_, together with the corresponding parent/child links. G. Madariaga 1997-07-21 added _audit_link_external_block_ items G. Madariaga 1997-07-21 added _reflns_shell_by_class_ items G. Madariaga 1997-07-22 added _atom_site_spec_func_disp_axis and _atom_site_spec_func_rot_axis G. Madariaga 1997-07-22 added new *_wave_vector *_wave_vector_seq_id and *_wave_vector_ items G. Madariaga 1997-07-22 added *_temp_element_ items G. Madariaga 1997-07-23 *_sup_spac_sy_ items reworded as *_superspace_symm_. _refine_ls_mod_funct_description reworded as _refine_ls_modulation_function. G. Madariaga 1997-07-23 *_wave_vector_ items changed: defined generic _atom_site_Fourier_wave_vector_ and new link/parent relationships with *_disp_wave_vector_seq_id, *_occ_wave_vector_seq_id, *_rot_wave_vector_seq_id, *_temp_wave_vector_seq_id. G. Madariaga 1997-07-24 added _atom_site_spec_param_temp_B and _atom_site_spec_param_temp_U G. Madariaga 1997-07-24 ********Cyclops test passed*********** G. Madariaga 1997-07-28 _refine_ls_subsystem_ items renamed to _cell_subsystem_. _cell_numb_of_subsystems renamed to _cell_subsystem_number G. Madariaga 1997-07-29 _cell_reciprocal_basis_vect_numb renamed to _cell_reciprocal_basis_vect_number. _diffrn_reflns_number_of_classes renamed to _diffrn_reflns_class_number G. Madariaga 1997-11-12 References to the B form of temperature factors removed I.D. Brown 1997-11-12 Some spelling mistakes corrected. I.D. Brown 1997-12-12 _atom_site_Fourier_disp_sin removed from _list_reference of _atom_site_Fourier_disp_cos. _atom_site_Fourier_disp_phase removed from _list_reference of _atom_site_Fourier_disp_modulus. _atom_site_Fourier_disp_modulus removed from _list_reference of _atom_site_Fourier_disp_phase. _atom_site_Fourier_disp_cos removed from _list_reference of _atom_site_Fourier_disp_sin. _atom_site_Fourier_occ_sin removed from _list_reference of _atom_site_Fourier_occ_cos. _atom_site_Fourier_occ_phase removed from _list_reference of _atom_site_Fourier_occ_modulus. _atom_site_Fourier_occ_modulus removed from _list_reference of _atom_site_Fourier_occ_phase. _atom_site_Fourier_occ_cos removed from _list_reference of _atom_site_Fourier_occ_sin. _atom_site_Fourier_rot_sin removed from _list_reference of _atom_site_Fourier_rot_cos. _atom_site_Fourier_rot_phase removed from _list_reference of _atom_site_Fourier_rot_modulus. _atom_site_Fourier_rot_modulus removed from _list_reference of _atom_site_Fourier_rot_phase. _atom_site_Fourier_rot_cos removed from _list_reference of _atom_site_Fourier_rot_sin. _atom_site_Fourier_temp_sin_U_ removed from _list_reference of _atom_site_Fourier_cos_U_. _atom_site_Fourier_temp_phase_U_ removed from _list_reference of _atom_site_Fourier_modulus_U_. _atom_site_Fourier_temp_modulus_U_ removed from _list_reference of _atom_site_Fourier_phase_U_. _atom_site_Fourier_temp_cos_U_ removed from _list_reference of _atom_site_Fourier_sin_U_. B. McMahon P. Edgington 1997-12-12 Several typos corrected P. Edgington 1997-12-12 Tabs removed P. Edgington 1997-12-15 _enumeration_range 0.0: added to the following items: _atom_site_Fourier_disp_modulus _atom_site_Fourier_occ_modulus _atom_site_Fourier_rot_modulus _atom_site_Fourier_temp_modulus_U_ _atom_site_phason_coeff _cell_wave_vector_pressure_ _cell_wave_vector_temp_ _refine_ls_overall_phason_coeff. _enumeration_range 0: added to the following items: _diffrn_reflns_by_class_number _reflns_shell_by_class_number_measured_all _reflns_shell_by_class_number_measured_obs _enumeration_range 1:192 added to _symmetry_equiv_position_number _enumeration_range 1.1: added to _symmetry_superspace_group_numb_IT P. Edgington 1997-12-15 'obs' and 'observed' changed to 'gt'. References to '_reflns_observed_criterion' changed to '_reflns_threshold_expression' B. McMahon 1997-12-15 Items including *_superspace_symm_, _superspace_ and _symmetry_, renamed to _ssg_symmetry_ or _symmetry_ssg_ (where appropriate). 'ssg' holds for 'superspace group' I.D. Brown G. Madariaga B. McMahon 1997-12-15 _symmetry_ssg_numb_WJJ renamed to _symmetry_ssg_code_WJJ G. Madariaga 1997-12-16 _atom_site_mod_refinement_flags split into _atom_site_disp_refinement_flag, _atom_site_occ_refinement_flag, _atom_site_temp_refinement_flag I.D. Brown P. Edgington 1997-12-17 The following items: _atom_site_spec_param_disp_code, _atom_site_spec_param_occ_code, _atom_site_spec_param_rot_code, _atom_site_spec_param_temp_code, _atom_site_spec_param_disp, _atom_site_spec_param_occ, _atom_site_spec_param_rot, _atom_site_spec_param_temp_U, _cell_matrix_W_ renamed as: _atom_site_spec_func_disp_param_code, _atom_site_spec_func_occ_param_code, _atom_site_spec_func_rot_param_code, _atom_site_spec_func_temp_param_code, _atom_site_spec_func_disp_param, _atom_site_spec_func_occ_param, _atom_site_spec_func_rot_param, _atom_site_spec_func_temp_param_U, _cell_subsystem_matrix_W_ for a better introduction of new categories G. Madariaga 1997-12-18 new categories defined: ATOM_SITE_FOURIER_DISP, ATOM_SITE_FOURIER_OCC, ATOM_SITE_FOURIER_ROT, ATOM_SITE_FOURIER_TEMP, ATOM_SITE_FOURIER-WAVE_VECTOR, ATOM_SITE_SPEC_FUNC_DISP, ATOM_SITE_SPEC_FUNC_OCC, ATOM_SITE_SPEC_FUNC_ROT, ATOM_SITE_SPEC_FUNC_TEMP, CELL_SUBSYSTEM, CELL_WAVE_VECTOR, DIFFRN_REFLNS_CLASS, REFINE_LS_CLASS, REFINE_LS_SPEC_FUNC_DISP, REFINE_LS_SPEC_FUNC_OCC, REFINE_LS_SPEC_FUNC_ROT, REFINE_LS_SPEC_FUNC_TEMP, REFINE_LS_SPEC_PARAM_DISP, REFINE_LS_SPEC_PARAM_OCC, REFINE_LS_SPEC_PARAM_ROT, REFINE_LS_SPEC_PARAM_TEMP, REFLNS_CLASS, REFINE_SHELL_CLASS, SYMMETRY_SSG_EQUIV B. McMahon 1997-12-18 added the appropriate items belonging to CATEGORY_OVERVIEW and some examples. Dictionary arranged a la Core. G. Madariaga 1997-12-18 ********vcif test passed*********** G. Madariaga 1998-01-08 *_U_ items converted to *_U (redundancy) G. Madariaga 1998-05-20 Major changes: The abbreviation 'temp' for 'temperature factor' has been substituted by 'U'. It affects the following categories and datanames: ATOM_SITE_FOURIER_TEMP _atom_site_Fourier_temp_label _atom_site_Fourier_temp_element_U _atom_site_Fourier_temp_cos_U _atom_site_Fourier_temp_modulus_U _atom_site_Fourier_temp_phase_U _atom_site_Fourier_temp_sin_U _atom_site_Fourier_temp_wave_vector_seq_id ATOM_SITE_SPEC_FUNC_TEMP _atom_site_spec_func_temp_element_U _atom_site_spec_func_temp_label _atom_site_spec_func_temp_param_code _atom_site_spec_func_temp_param_U REFINE_LS_SPEC_FUNC_TEMP _refine_ls_spec_func_temp _refine_ls_spec_func_temp_code REFINE_LS_SPEC_PARAM_TEMP _refine_ls_spec_param_temp _refine_ls_spec_param_temp_code _diffrn_reflns_by_class_number renamed to _diffrn_reflns_class_number_of_reflns _reflns_by_class_number_ renamed to _reflns_class_number_of_reflns_ The part '_by_class' has been substituted by 'class' for a better link to the category name. Affected datanames are: _diffrn_reflns_by_class_av_R_eq _diffrn_reflns_by_class_av_sgI/I _diffrn_reflns_by_class_number _diffrn_reflns_by_class_th_ _refine_ls_by_class_res_ _refine_ls_by_class_R_factor_ _refine_ls_by_class_R_Fsqd_factor _refine_ls_by_class_R_I_factor _refine_ls_by_class_wR_factor_ _reflns_by_class_number_ _reflns_shell_by_class_d_res_ _reflns_shell_by_class_meanI_over_sigI_ _reflns_shell_by_class_number_measured_ _reflns_shell_by_class_number_possible _reflns_shell_by_class_number_unique_ _reflns_shell_by_class_percent_possible_ _reflns_shell_by_class_Rmerge_ *_extra_index_ renamed to *_index_m_. list of affected datanames: _diffrn_refln_extra_index_ _diffrn_reflns_limit_extra_index_ _diffrn_standard_refln_extra_index_ _exptl_crystal_face_extra_index_ _refln_extra_index_ _reflns_limit_extra_index_ _diffrn_reflns_class renamed to _diffrn_reflns_class_description. _diffrn_reflns_class_number renamed to _diffrn_reflns_number_of_classes. _diffrn_reflns_sat_maximum_order renamed to _diffrn_reflns_satellite_order_max. _diffrn_symmetry renamed to _diffrn_symmetry_description _refine_ls_class_wR_factor_gt removed. _symmetry_ssg_equiv_position_number renamed to _symmetry_ssg_equiv_positions_number. I.D. Brown 1998-05-20 Less major and minor changes: Several examples looped correctly. Some typos corrected. I.D. Brown 1998-05-21 _enumeration_range of _atom_site_rot_modulus changed from 0.0:360.0 to 0.0: Added _enumeration_default 0 to _cell_subsystem_matrix_W_ I.D. Brown 1998-05-21 More major changes: _disp substituted by _displace since the latter abbreviation already exists in coreCIF. However some datanames (like _atom_site_Fourier_displace_wave_vector_seq_id) are probably too long. Let's try anyway. _atom_site_Fourier_displace_, _atom_site_Fourier_occ_, _atom_site_Fourier_rot_ and _atom_site_Fourier_U_ items renamed to: _atom_site_displace_Fourier_, _atom_site_occ_Fourier_, _atom_site_rot_Fourier_ and _atom_site_U_Fourier_. The corresponding categories have been similarly changed I.D. Brown 1998-05-21 _atom_site_Fourier_wave_vector_seq_id included as _list_reference of _atom_site_Fourier_wave_vector_ G. Madariaga 1998-05-21 *_spec_func_ -> *_special_func_ I.D. Brown 1998-05-22 *_spec_param_ -> *_special_param_ I.D. Brown 1998-05-22 _atom_site_special_func_displace_, _atom_site_special_func_occ_, _atom_site_special_func_rot_ and _atom_site_special_func_U_ items renamed to: _atom_site_displace_special_func_, _atom_site_occ_special_func_, _atom_site_rot_special_func_ and _atom_site_U_special_func_. _refine_ls_special_func_displace_, _refine_ls_special_func_occ_, _refine_ls_special_func_rot_ and _refine_ls_special_func_U_ items renamed to: _refine_ls_displace_special_func_, _refine_ls_occ_special_func_, _refine_ls_rot_special_func_ and _refine_ls_U_special_func_. _refine_ls_special_param_displace_, _refine_ls_special_param_occ_, _refine_ls_special_param_rot_ and _refine_ls_special_param_U_ items renamed to: _refine_ls_displace_special_param_, _refine_ls_occ_special_param_, _refine_ls_rot_special_param_ and _refine_ls_U_special_param_. The corresponding categories have been similarly changed G. Madariaga 1998-05-22 *_Fourier_label -> *_Fourier_atom_site_label *_special_func_label -> *_special_func_atom_site_label 'element' referred to the temperature factor U changed to 'tens_elem' I.D. Brown 1998-05-25 *_refinement_flag -> *_modulation_flag I.D. Brown 1998-05-25 _refine_ls_*_special_param_ items renamed to _refine_ls_*_special_func_param_ G. Madariaga 1998-05-26 _refine_ls_restrained_wR_gt deleted G. Madariaga 1998-05-27 _diffrn_reflns_th_ renamed to _diffrn_reflns_class_d_res_ I.D. Brown 1998-05-27 _symmetry_ssg_equiv_pos_as_fract_coord renamed to _symmetry_ssg_equiv_pos_as_xyz I.D. Brown 1998-08-03 Fixed some typos; removed global_ block B. McMahon 1998-08-04 Moved _diffrn_pressure_history and _diffrn_thermal_history to core as _exptl_crystal_pressure_history and _exptl_crystal_thermal_history; moved _diffrn_symmetry_description and REFINE_LS_CLASS to core B. McMahon 1998-12-08 Version spellchecked and checked with vcif and cyclops, then returned to Gotzon B. McMahon 1998-12-23 Categories involving special functions cross- referenced. Some examples enlarged. I.D. Brown 1998-12-23 Some items and categories alphabetically reordered. G. Madariaga 1998-12-23 _atom_site_phason_label renamed to _atom_site_phason_atom_site_label G. Madariaga 1998-12-23 _diffrn_reflns_number_of_classes removed. G. Madariaga 1998-12-23 Merging of the following pairs of definitions: _reflns_shell_class_d_res_high and _reflns_shell_class_d_res_low _reflns_shell_class_meanI_over_sigI_all and _reflns_shell_class_meanI-over_sigI_gt _reflns_shell_class_number_measured_all and _reflns_shell_class_number_measured_gt _reflns_shell_class_number_unique_all and _reflns_shell_class_number_unique_gt _reflns_shell_class_percent_possible_all and _reflns_shell_class_percent_possible_gt _reflns_shell_class_Rmerge_F_all and _reflns_shell_class_Rmerge_F_gt _reflns_shell_class_Rmerge_I_all and _reflns_shell_class_Rmerge_I_gt. H. Flack 1998-12-27 Modified the definitions of: _atom_site_Fourier_wave_vector_, _cell_wave_vector_, _cell_subsystem_matrix_W_, _symmetry_ssg_name, _symmetry_ssg_name_IT and _symmetry_ssg_name_WJJ G. Madariaga 1999-01-14 Added the following datanames: _atom_site_phason_subsystem_code _atom_site_aniso_subsystem_code _atom_site_displace_Fourier_subsystem_code _atom_site_occ_Fourier_subsystem_code _atom_site_rot_Fourier_subsystem_code _atom_site_U_Fourier_subsystem_code _atom_site_displace_special_func_subsystem_code _atom_site_occ_special_func_subsystem_code _atom_site_rot_special_func_subsystem_code _atom_site_U_special_func_subsystem_code _geom_angle_atom_site_subsystem_code_ _geom_bond_atom_site_subsystem_code_ _geom_contact_atom_site_subsystem_code_ _geom_torsion_atom_site_subsystem_code_ V. Petricek 1999-01-24 More examples added to ATOM_SITE_DISPLACE_FOURIER G. Madariaga 1999-02-28 _enumeration list of: _atom_site_displace_Fourier_axis, _atom_site_rot_Fourier_axis, _atom_site_displace_special_func_axis and _atom_site_rot_special_func_axis enlarged to cover arbitrary axes different from the crystallographic ones. G. Madariaga 1999-02-28 New datanames: _atom_site_displace_Fourier_axes_description, _atom_site_rot_Fourier_axes_description, _atom_site_displace_special_func_axes_description and _atom_site_rot_special_func_axes_description. G. Madariaga 1999-02-28 Modified the definitions of: _atom_site_displace_Fourier_cos, _atom_site_displace_Fourier_modulus and _atom_site_displace_Fourier_sin G. Madariaga 1999-02-28 A new example added to ATOM_SITE_ROT_FOURIER and ATOM_SITE_DISPLACE_FOURIER G. Madariaga 1999-04-01 Some cosmetic rearrangement of line endings to improve the formatted version B. McMahon 1999-04-19 DIFFRN_REFLNS_CLASS and REFLNS_CLASS removed (already in cif_core.dic 2.1) _atom_site_Fourier_wave_vector renamed to _atom_site_Fourier_wave_vector_description _cell_reciprocal_basis renamed to _cell_reciprocal_basis_description _cell_subsystem renamed to _cell_subsystem_description _refine_ls_hydrogen_mod_param renamed to _refine_ls_hydrogen_mod_flag _refine_ls_*_special_func renamed to _refine_ls_*_special_func_description. I.D. Brown 1999-04-19 _symmetry_equiv_position_number: _enumeration_range 1:192 changed to _enumeration_range 1: I.D. Brown 1999-04-19 _refine_ls_*_special_func_param renamed to _refine_ls_*_special_func_param_description. G. Madariaga 1999-07-26 New datanames: _atom_site_modulation_global_phase_t_ G. Madariaga 1999-07-29 A caution about the names of the items belonging to SYMMETRY and SYMMETRY_SSG_EQUIV categories I.D. Brown 1999-07-29 Definition of _atom_site_Fourier_wave_vector_ reworded G. Madariaga 1999-07-29 Definition of _cell_subsystem_matrix_W_ completely reworded G. Madariaga 1999-07-29 ********vcif test passed*********** G. Madariaga 2000-04-20 merged Gotzon's revisions/my cosmetic changes B. McMahon 2000-07-06 _aver -> _av in several _geom definitions _type_construct entries commented out pending some software implementation of _type_construct validation new categories added in several cases to house data items that give collective descriptions of other items individually looped together; new categories are ATOM_SITES_DISPLACE_FOURIER, ATOM_SITES_DISPLACE_SPECIAL_FUNC, ATOM_SITES_ROT_FOURIER, ATOM_SITES_ROT_SPECIAL_FUNC, CELL_WAVE_VECTORS several stylistic and punctuation changes B. McMahon 2000-07-19 Some further changes during COMCIFS review: removed _audit_link_external_block_code and *_description pending reworking of core AUDIT_LINK category to include external blocks. Description of the recommended usage for block codes in modulated structures moved to the discussion in data_audit_link_[ms]. [ms] added consistently to category descriptions specific to this dictionary REFLNS_SHELL_CLASS category removed because this functionality is met in the Core by REFLNS_CLASS moved _refine_ls_F_calc_accuracy, *_details, *_formula, _refine_ls_restrained_wR_all, *_weighting_scheme to core _refine_ls_hydrogen_mod_flag, _refine_ls_modulation_func_description, _refine_ls_overall_phason_coeff, _refine_ls_overall_phason_formula renamed as _refine_ls_mod_hydrogen_treatment, _refine_ls_mod_func_description, _refine_ls_mod_overall_phason_coeff, _refine_ls_mod_overall_phason_formula, respectively First attempt to rename symmetry data names in with the symcif proposals by changing _symmetry_ to _space_group_ throughout. The thinking is that the _ssg_ flag will indicate superspace group within the existing (draft) SPACE_GROUP category. I.D.Brown suggests that there is no need for a special category for equivalent positions; but I'm not sure at this stage, and retain Gotzon's proposal until further consideration is given to how to phase out the old core _symmetry_ names _symmetry_ssg_equiv_pos_as_xyz renamed _space_group_ssg_equiv_pos_algebraic for greater generality Added example to _space_group_ssg_code_WJJ B. McMahon 2000-10-16 Some additional changes: -symmetry items. Changes consistent with cif_sym.0.07: _space_group_ssg_numb_IT changed to _space_group_ssg_IT_number. SPACE_GROUP_SSG_EQUIV category changed to SPACE_GROUP_SYMOP. _space_group_ssg_equiv_pos_algebraic, _space_group_ssg_equiv_pos_seg_id changed to _space_group_symop_ssg_operation_algebraic, _space_group_symop_ssg_id. _space_group_equivalent_position_number changed to _space_group_symop_ssg_operations_number and therefore changed from SPACE_GROUP to SPACE_GROUP_SYMOP 'equivalent position' replaced by 'symmetry operation' where neccessary (see _geom_*_site_symmetry_ items). -New category ATOM_SITES_MODULATION. It contains only the _atom_sites_modulation_global_phase_t_ items. -Some minors changes. Reference to JANA98 changed to JANA2000. Some references corrected. G. Madariaga 2001-04-19 Treatment of special functions completely changed. The categories: ATOM_SITE_ROT_SPECIAL_FUNC ATOM_SITE_U_SPECIAL_FUNC ATOM_SITES_DISPLACE_SPECIAL_FUNC ATOM_SITES_ROT_SPECIAL_FUNC REFINE_LS_DISPLACE_SPECIAL_FUNC REFINE_LS_DISPLACE_SPECIAL_FUNC_PARAM REFINE_LS_OCC_SPECIAL_FUNC REFINE_LS_OCC_SPECIAL_FUNC_PARAM REFINE_LS_ROT_SPECIAL_FUNC REFINE_LS_ROT_SPECIAL_FUNC_PARAM REFINE_LS_U_SPECIAL_FUNC REFINE_LS_U_SPECIAL_FUNC_PARAM have been removed. The categories ATOM_SITE_DISPLACE_SPECIAL_FUNC and ATOM_SITE_OCC_SPECIAL_FUNC have suffered the following changes: _atom_site_displace_special_func_axis, _atom_site_displace_special_func_param, _atom_site_displace_special_func_param_code, _atom_site_displace_occ_func_param, _atom_site_displace_occ_func_param_code have been removed and substituted by: _atom_site_displace_special_func_sawtooth_, _atom_site_occ_special_func_crenel_. All the examples have been accordingly changed. The categories: ATOM_SITE_DISPLACE_FOURIER, ATOM_SITE_OCC_FOURIER, ATOM_SITE_ROT_FOURIER, ATOM_SITE_U_FOURIER have been split. There are four new categories: ATOM_SITE_DISPLACE_FOURIER_PARAM, ATOM_SITE_OCC_FOURIER_PARAM, ATOM_SITE_ROT_FOURIER_PARAM, ATOM_SITE_U_FOURIER_PARAM linked with the former ones through two new items: _atom_site_displace_Fourier_id, _atom_site_displace_Fourier_param_id which are the _list_reference for the all the items in each category. The examples have been changed and some definitions slightly reworded. Added the new category ATOM_SITE_PHASON. Some cosmetic changes. I.D. Brown J.Westbrook 2001-05-12 *_subsystem_code items deleted except for _atom_site_subsystem_code; corrected _list_reference for _atom_site_Fourier_wave_vector_description and _list_link_parent for _atom_site_U_Fourier_param_id; moved _space_group_symop_ssg_operations_number to category space_group as _space_group_ssg_symops_number (all suggestions of IDB) B. McMahon 2001-05-28 _space_group_ssg_symops_number and _cell_reciprocal_basis_vect_number now appear as comments. They are only useful for some _type_construct regex. _cell_reciprocal_basis_vect_number has been substituted by (_cell_modulation_dimension + 3) in some definitions. G. Madariaga 2002-02-28 Definitions of: _space_group_[ms], _space_group_ssg_name, _space_group_ssg_name_IT, _space_group_ssg_name_WJJ and _space_group_symop_[ms] reworded according to the rules given in the dictionary cif_sym 1.0. G. Madariaga 2002-02-04 Release version 1.0. IUCr (B. McMahon) 2002-03-04 Cosmetic edits for formatted version B. McMahon 2004-06-10 Further cosmetic edits for formatting in International Tables Volume G B. McMahon 2005-01-06 Some realphabetisation B. McMahon 2005-01-17 NJ Ashcroft: minor corrections to hyphenation, spelling and punctuation _audit_link_[ms]: definition edited slightly _cell_wave_vectors_pressure_, _cell_wave_vectors_temp_: definition edited slightly _exptl_crystal_type_of_structure: definition edited _space_group_ssg_IT_number, data_space_group_ssg_name_IT: reference to Vol. C updated _geom_torsion_: reference changed from Endeavour to Experientia 2005-03-27 Addition of changes included in ITCG chapter 4.3 G. Madariaga 2005-06-16 Category overviews added for all categories NJ Ashcroft ; ############### ## ATOM_SITE ## ############### data_atom_site[ms] _name '_atom_site_[ms]' _category category_overview _type null _definition ; Data items in the ATOM_SITE category record details about the atom sites in a crystal structure, such as the positional coordinates, atomic displacement parameters, and magnetic moments and directions. This category exists in the core CIF dictionary but is extended in this dictionary by the addition of some items that may appear in the main looped list of atom-site information. ; data_atom_site_displace_modulation_flag _name '_atom_site_displace_modulation_flag' _category atom_site _type char _list yes _list_reference '_atom_site_label' loop_ _enumeration _enumeration_detail 'yes' 'displacive modulation' 'y' 'abbreviation for "yes"' 'no' 'no displacive modulation' 'n' 'abbreviation for "no"' _enumeration_default 'no' _definition ; A code that signals whether the structural model includes the modulation of the positional coordinates of a given atom site. ; data_atom_site_occ_modulation_flag _name '_atom_site_occ_modulation_flag' _category atom_site _type char _list yes _list_reference '_atom_site_label' loop_ _enumeration _enumeration_detail 'yes' 'occupational modulation' 'y' 'abbreviation for "yes"' 'no' 'no occupational modulation' 'n' 'abbreviation for "no"' _enumeration_default 'no' _definition ; A code that signals whether the structural model includes the modulation of the occupation of a given atom site. ; data_atom_site_subsystem_code _name '_atom_site_subsystem_code' _category atom_site _type char _list yes _list_reference '_atom_site_label' _list_link_parent '_cell_subsystem_code' _definition ; A code that links a given atom or rigid-group site to one of the subsystems present in a composite. This code provides an alternative description for composites which is less explicit than that based on linked data blocks (see the description in this dictionary of _audit_link_[ms]). It must match one of the labels specified for _cell_subsystem_code. ; data_atom_site_U_modulation_flag _name '_atom_site_U_modulation_flag' _category atom_site _type char _list yes _list_reference '_atom_site_label' loop_ _enumeration _enumeration_detail 'yes' 'modulation of thermal parameters' 'y' 'abbreviation for "yes"' 'no' 'no modulation of thermal parameters' 'n' 'abbreviation for "no"' _enumeration_default 'no' _definition ; A code that signals whether the structural model includes the modulation of the thermal parameters of a given atom site. ; ################################ ## ATOM_SITE_DISPLACE_FOURIER ## ################################ data_atom_site_displace_Fourier_[] _name '_atom_site_displace_Fourier_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_description 1 0.568 'First harmonic' 2 1.136 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nb1z1 Nb1 z 1 Nb1x2 Nb1 x 2 Nb1y2 Nb1 y 2 S1x1 S1 x 1 S1y1 S1 y 1 S1z1 S1 z 1 S1x2 S1 x 2 S1y2 S1 y 2 S1z2 S1 z 2 ; ; Example 1 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; # NbS2 subsystem has been chosen as reference, i.e. its # W matrix is the unit matrix. loop_ _cell_subsystem_code _cell_subsystem_description _cell_subsystem_matrix_W_1_1 _cell_subsystem_matrix_W_1_4 _cell_subsystem_matrix_W_2_2 _cell_subsystem_matrix_W_3_3 _cell_subsystem_matrix_W_4_1 _cell_subsystem_matrix_W_4_4 NbS2 '1st subsystem' 1 0 1 1 0 1 LaS '2nd subsystem' 0 1 1 1 1 0 # The modulation wave vectors are referred to the reciprocal # basis of each subsystem. They are related to the reciprocal # basis used to index the whole diffraction pattern through # the W matrices. loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_z _atom_site_Fourier_wave_vector_description 1 0.568 0 'First harmonic' 2 1.136 0 'Second harmonic' 3 1.761 0.5 'First harmonic' 4 3.522 1.0 'Second harmonic' # The modulation coefficients given below are referred to # each subsystem. loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nb1z1_NbS2 Nb1 z 1 Nb1x2_NbS2 Nb1 x 2 Nb1y2_NbS2 Nb1 y 2 S1x1_NbS2 S1 x 1 S1y1_NbS2 S1 y 1 S1z1_NbS2 S1 z 1 S1x2_NbS2 S1 x 2 S1y2_NbS2 S1 y 2 S1z2_NbS2 S1 z 2 La1x3_LaS La1 x 3 La1y3_LaS La1 y 3 La1z3_LaS La1 z 3 La1x4_LaS La1 x 4 La1y4_LaS La1 y 4 La1z4_LaS La1 z 4 S2x3_LaS S2 x 3 S2y3_LaS S2 y 3 S2z3_LaS S2 z 3 S2x4_LaS S2 x 4 S2y4_LaS S2 y 4 S2z4_LaS S2 z 4 ; ; Example 2 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; # # The same structural data but expressed using a set of # linked data blocks # # Items concerning the modulated structure of the first # subsystem data_LaSNbS2_MOD_NbS2 _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD_NbS2 loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (common data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (common data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' . 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_description 1 0.568 'First harmonic' 2 1.136 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nb1z1 Nb1 z 1 Nb1x2 Nb1 x 2 Nb1y2 Nb1 y 2 S1x1 S1 x 1 S1y1 S1 y 1 S1z1 S1 z 1 S1x2 S1 x 2 S1y2 S1 y 2 S1z2 S1 z 2 #### End of modulated structure first subsystem data ###### # Items concerning the modulated structure of the second # subsystem data_LaSNbS2_MOD_LaS _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD_LaS loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (common data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (common data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' . 'modulated structure (2nd subsystem)' loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_z _atom_site_Fourier_wave_vector_description 1 1.761 0.5 'First harmonic' 2 3.522 1.0 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id La1x1 La1 x 1 La1y1 La1 y 1 La1z1 La1 z 1 La1x2 La1 x 2 La1y2 La1 y 2 La1z2 La1 z 2 S2x1 S2 x 1 S2y1 S2 y 1 S2z1 S2 z 1 S2x2 S2 x 2 S2y2 S2 y 2 S2z2 S2 z 2 ### End of modulated structure second subsystem data ###### ; ; Example 3 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _atom_sites_displace_Fourier_axes_description ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Byphenyl_a1_1 Biphenyl a1 1 ; ; Example 4 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. Note the entry from the ATOM_SITES_DISPLACE_FOURIER category to describe collective information relating to all the atom sites. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_DISPLACE_FOURIER category record details about the Fourier components of the displacive modulation of an atom site in a modulated structure. In the case of rigid groups, items in this category would only include the translational part of the modulation. The rotational part would appear in a separate list of items belonging to the ATOM_SITE_ROT_FOURIER category. The (in general complex) coefficients of each Fourier component belong to the category ATOM_SITE_DISPLACE_FOURIER_PARAM and are listed separately. ; data_atom_site_displace_Fourier_atom_site_label _name '_atom_site_displace_Fourier_atom_site_label' _category atom_site_displace_Fourier _type char _list yes _list_reference '_atom_site_displace_Fourier_id' _list_link_parent '_atom_site_label' _definition ; Modulation parameters are usually looped in separate lists. Modulated parameters are the atom positions (displacive modulation), the atomic occupation (occupational modulation) and/or the atomic anisotropic (or isotropic) displacement parameters (referred to as modulation of thermal parameters, since the term 'displacement parameters' is ambiguous in this context). _atom_site_displace_Fourier_atom_site_label is the code that identifies an atom or rigid group in a loop in which the Fourier components of its displacive modulation are listed. In the case of a rigid group, this list would only include the translational part of its displacive modulation. The rotational part (if any) would appear in a separate list (see _atom_site_rot_Fourier_atom_site_label). This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_displace_Fourier_axis _name '_atom_site_displace_Fourier_axis' _category atom_site_displace_Fourier _type char _list yes _list_reference '_atom_site_displace_Fourier_id' loop_ _enumeration _enumeration_detail x 'displacement along the a axis' y 'displacement along the b axis' z 'displacement along the c axis' a1 'displacement along an arbitrary a1 axis' a2 'displacement along an arbitrary a2 axis' a3 'displacement along an arbitrary a3 axis' _definition ; A label identifying the displacement component of a given atom or rigid group that is being parameterized by Fourier series. a, b and c are the basic lattice vectors of the reference structure. For composites they refer to the reference structure of each subsystem. a1, a2 and a3 are defined by _atom_sites_displace_Fourier_axes_description. ; data_atom_site_displace_Fourier_id _name '_atom_site_displace_Fourier_id' _category atom_site_displace_Fourier _type char _list yes _list_mandatory yes _list_link_child '_atom_site_displace_Fourier_param_id' _definition ; A code identifying each component of the displacive modulation of a given atom or rigid group when the modulation is expressed in terms of Fourier series. In the case of a rigid group, it applies only to the translational part of the distortion. ; data_atom_site_displace_Fourier_wave_vector_seq_id _name '_atom_site_displace_Fourier_wave_vector_seq_id' _category atom_site_displace_Fourier _type numb _list yes _list_reference '_atom_site_displace_Fourier_id' _list_link_parent '_atom_site_Fourier_wave_vector_seq_id' _definition ; A numeric code identifying the wave vectors of the Fourier terms used in the structural model to describe the displacive modulation of an atom or rigid group. In the case of a rigid group, it applies only to the translational part of the distortion. This code must match _atom_site_Fourier_wave_vector_seq_id. ; ###################################### ## ATOM_SITE_DISPLACE_FOURIER_PARAM ## ###################################### data_atom_site_displace_Fourier_param_[] _name '_atom_site_displace_Fourier_param_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_description 1 0.568 'First harmonic' 2 1.136 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nb1z1 Nb1 z 1 Nb1x2 Nb1 x 2 Nb1y2 Nb1 y 2 S1x1 S1 x 1 S1y1 S1 y 1 S1z1 S1 z 1 S1x2 S1 x 2 S1y2 S1 y 2 S1z2 S1 z 2 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_cos _atom_site_displace_Fourier_param_sin Nb1z1 -0.0006(2) 0. Nb1x2 0. 0.0078(17) Nb1y2 -0.0014(7) 0. S1x1 0. -0.0134(85) S1y1 -0.0022(12) 0. S1z1 0.0014(14) 0. S1x2 0. -0.0129(27) S1y2 -0.0073(27) 0. S1z2 -0.0012(3) 0. ; ; Example 1 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; # NbS2 subsystem has been chosen as reference, i.e. its # W matrix is the unit matrix. loop_ _cell_subsystem_code _cell_subsystem_description _cell_subsystem_matrix_W_1_1 _cell_subsystem_matrix_W_1_4 _cell_subsystem_matrix_W_2_2 _cell_subsystem_matrix_W_3_3 _cell_subsystem_matrix_W_4_1 _cell_subsystem_matrix_W_4_4 NbS2 '1st subsystem' 1 0 1 1 0 1 LaS '2nd subsystem' 0 1 1 1 1 0 # The modulation wave vectors are referred to the reciprocal # basis of each subsystem. They are related to the reciprocal # basis used to index the whole diffraction pattern through # the W matrices. loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_z _atom_site_Fourier_wave_vector_description 1 0.568 0 'First harmonic' 2 1.136 0 'Second harmonic' 3 1.761 0.5 'First harmonic' 4 3.522 1.0 'Second harmonic' # The modulation coefficients given below are referred to # each subsystem. loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nb1z1_NbS2 Nb1 z 1 Nb1x2_NbS2 Nb1 x 2 Nb1y2_NbS2 Nb1 y 2 S1x1_NbS2 S1 x 1 S1y1_NbS2 S1 y 1 S1z1_NbS2 S1 z 1 S1x2_NbS2 S1 x 2 S1y2_NbS2 S1 y 2 S1z2_NbS2 S1 z 2 La1x3_LaS La1 x 3 La1y3_LaS La1 y 3 La1z3_LaS La1 z 3 La1x4_LaS La1 x 4 La1y4_LaS La1 y 4 La1z4_LaS La1 z 4 S2x3_LaS S2 x 3 S2y3_LaS S2 y 3 S2z3_LaS S2 z 3 S2x4_LaS S2 x 4 S2y4_LaS S2 y 4 S2z4_LaS S2 z 4 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_cos _atom_site_displace_Fourier_param_sin Nb1z1_NbS2 -0.0006(2) 0. Nb1x2_NbS2 0. 0.0078(17) Nb1y2_NbS2 -0.0014(7) 0. S1x1_NbS2 0. -0.0134(85) S1y1_NbS2 -0.0022(12) 0. S1z1_NbS2 0.0014(14) 0. S1x2_NbS2 0. -0.0129(27) S1y2_NbS2 -0.0073(27) 0. S1z2_NbS2 -0.0012(3) 0. La1x3_LaS 0. -0.0010(22) La1y3_LaS 0.0174(4) 0. La1z3_LaS -0.0005(3) 0. La1x4_LaS 0. 0.0144(7) La1y4_LaS 0.0001(14) 0. La1z4_LaS 0.0008(3) 0. S2x3_LaS 0. 0.0059(70) S2y3_LaS 0.0081(16) 0. S2z3_LaS 0.0009(12) 0. S2x4_LaS 0. -0.0030(30) S2y4_LaS 0.0002(56) 0. S2z4_LaS 0.0007(10) 0. ; ; Example 2 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; # # The same structural data but expressed using a set of linked data blocks # # Items concerning the modulated structure of the first # subsystem data_LaSNbS2_MOD_NbS2 _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD_NbS2 loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (common data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (common data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' . 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_description 1 0.568 'First harmonic' 2 1.136 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nb1z1 Nb1 z 1 Nb1x2 Nb1 x 2 Nb1y2 Nb1 y 2 S1x1 S1 x 1 S1y1 S1 y 1 S1z1 S1 z 1 S1x2 S1 x 2 S1y2 S1 y 2 S1z2 S1 z 2 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_cos _atom_site_displace_Fourier_param_sin Nb1z1 -0.0006(2) 0. Nb1x2 0. 0.0078(17) Nb1y2 -0.0014(7) 0. S1x1 0. -0.0134(85) S1y1 -0.0022(12) 0. S1z1 0.0014(14) 0. S1x2 0. -0.0129(27) S1y2 -0.0073(27) 0. S1z2 -0.0012(3) 0. #### End of modulated structure first subsystem data ###### # Items concerning the modulated structure of the second # subsystem data_LaSNbS2_MOD_LaS _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD_LaS loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (common data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (common data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' . 'modulated structure (2nd subsystem)' loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_z _atom_site_Fourier_wave_vector_description 1 1.761 0.5 'First harmonic' 2 3.522 1.0 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id La1x1 La1 x 1 La1y1 La1 y 1 La1z1 La1 z 1 La1x2 La1 x 2 La1y2 La1 y 2 La1z2 La1 z 2 S2x1 S2 x 1 S2y1 S2 y 1 S2z1 S2 z 1 S2x2 S2 x 2 S2y2 S2 y 2 S2z2 S2 z 2 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_cos _atom_site_displace_Fourier_param_sin La1x1 0. -0.0010(22) La1y1 0.0174(4) 0. La1z1 -0.0005(3) 0. La1x2 0. 0.0144(7) La1y2 0.0001(14) 0. La1z2 0.0008(3) 0. S2x1 0. 0.0059(70) S2y1 0.0081(16) 0. S2z1 0.0009(12) 0. S2x2 0. -0.0030(30) S2y2 0.0002(56) 0. S2z2 0.0007(10) 0. ### End of modulated structure second subsystem data ###### ; ; Example 3 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _atom_sites_displace_Fourier_axes_description ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Byphenyl_a1_1 Biphenyl a1 1 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_modulus _atom_site_displace_Fourier_param_phase Byphenyl_a1_1 0.035(5) 0. ; ; Example 4 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. Note the entry from the ATOM_SITES_DISPLACE_FOURIER category to describe collective information relating to all the atom sites. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_DISPLACE_FOURIER_PARAM category record details about the coefficients of the Fourier series used to describe the displacive modulation of an atom or rigid group. In the case of rigid groups, items in this category would only include the translational part of the modulation. The rotational part would appear in a separate list of items belonging to the ATOM_SITE_ROT_FOURIER_PARAM category. The Fourier components are defined in the category ATOM_SITE_DISPLACE_FOURIER and are listed separately. ; data_atom_site_displace_Fourier_param_cos _name '_atom_site_displace_Fourier_param_cos' _category atom_site_displace_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_displace_Fourier_param_id' _enumeration_default 0.0 _definition ; The displacive distortion of a given atom or rigid group (see also _atom_site_rot_Fourier_param_cos) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Ac cos(2\p k r)+As sin(2\p k r), and the modulus-argument form, |A| cos(2\p k r+\f), where k is the wave vector of the term and r is the atomic average position. _atom_site_displace_Fourier_param_cos is the cosine coefficient (Ac) corresponding to the Fourier term defined by _atom_site_displace_Fourier_atom_site_label, _atom_site_displace_Fourier_axis and _atom_site_displace_Fourier_wave_vector_seq_id. Atomic or rigid- group displacements must be expressed as fractions of the unit cell or in angstroms if the modulations are referred to some special axes defined by _atom_sites_displace_Fourier_axes_description. ; data_atom_site_displace_Fourier_param_id _name '_atom_site_displace_Fourier_param_id' _category atom_site_displace_Fourier_param _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_displace_Fourier_id' _definition ; A code identifying the (in general complex) coefficient of each term present in the Fourier series describing the displacive modulation of a given atom or rigid group. In the case of a rigid group, it applies only to the translational part of the distortion. This code must match _atom_site_displace_Fourier_id. ; data_atom_site_displace_Fourier_param_modulus _name '_atom_site_displace_Fourier_param_modulus' _category atom_site_displace_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_displace_Fourier_param_id' _enumeration_range 0.0: _enumeration_default 0.0 _definition ; The displacive distortion of a given atom or rigid group (see also _atom_site_rot_Fourier_param_modulus) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Ac cos(2\p k r)+As sin(2\p k r), and the modulus-argument form, |A| cos(2\p k r+\f), where k is the wave vector of the term and r is the atomic average position. _atom_site_displace_Fourier_param_modulus is the modulus (|A|) of the complex amplitude corresponding to the Fourier term defined by _atom_site_displace_Fourier_atom_site_label, _atom_site_displace_Fourier_axis and _atom_site_displace_Fourier_wave_vector_seq_id. Atomic or rigid- group displacements must be expressed as fractions of the unit cell or in angstroms if the modulations are referred to some special axes defined by _atom_sites_displace_Fourier_axes_description. ; data_atom_site_displace_Fourier_param_phase _name '_atom_site_displace_Fourier_param_phase' _category atom_site_displace_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_displace_Fourier_param_id' _enumeration_range -1.0:1.0 _enumeration_default 0.0 _units cy _units_detail 'Cycles' _definition ; The displacive distortion of a given atom or rigid group (see also _atom_site_rot_Fourier_param_phase) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Ac cos(2\p k r)+As sin(2\p k r), and the modulus-argument form, |A| cos(2\p k r+\f), where k is the wave vector of the term and r is the atomic average position. _atom_site_displace_Fourier_param_phase is the phase (\f/2\p) in cycles of the complex amplitude corresponding to the Fourier term defined by _atom_site_displace_Fourier_atom_site_label, _atom_site_displace_Fourier_axis and _atom_site_displace_Fourier_wave_vector_seq_id. ; data_atom_site_displace_Fourier_param_sin _name '_atom_site_displace_Fourier_param_sin' _category atom_site_displace_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_displace_Fourier_param_id' _enumeration_default 0.0 _definition ; The displacive distortion of a given atom or rigid group (see also _atom_site_rot_Fourier_param_sin) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Ac cos(2\p k r)+As sin(2\p k r), and the modulus-argument form, |A| cos(2\p k r+\f), where k is the wave vector of the term and r is the atomic average position. _atom_site_displace_Fourier_param_sin is the sine coefficient (As) corresponding to the Fourier term defined by _atom_site_displace_Fourier_atom_site_label, _atom_site_displace_Fourier_axis, and _atom_site_displace_Fourier_wave_vector_seq_id. Atomic or rigid- group displacements must be expressed as fractions of the unit cell or in angstroms if the modulations are referred to some special axes defined by _atom_sites_displace_Fourier_axes_description. ; ################################### ## ATOM_SITE_FOURIER_WAVE_VECTOR ## ################################### data_atom_site_Fourier_wave_vector_[] _name '_atom_site_Fourier_wave_vector_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_description 1 0.568 'First harmonic' 2 1.136 'Second harmonic' ; ; Example 1 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_FOURIER_WAVE_VECTOR category record details about the wave vectors of the Fourier terms used in the structural model. ; data_atom_site_Fourier_wave_vector_description _name '_atom_site_Fourier_wave_vector_description' _category atom_site_Fourier_wave_vector _type char _list yes _list_reference '_atom_site_Fourier_wave_vector_seq_id' _example 'q(4)=q(1)+q(2)' _definition ; A description of the linear combination involved in a given Fourier wave vector used to describe the atomic modulation functions. ; data_atom_site_Fourier_wave_vector_seq_id _name '_atom_site_Fourier_wave_vector_seq_id' _category atom_site_Fourier_wave_vector _type numb _list yes loop_ _list_link_child '_atom_site_displace_Fourier_wave_vector_seq_id' '_atom_site_occ_Fourier_wave_vector_seq_id' '_atom_site_rot_Fourier_wave_vector_seq_id' '_atom_site_U_Fourier_wave_vector_seq_id' _definition ; A numeric code identifying the wave vectors defined in _atom_site_Fourier_wave_vector_. ; data_atom_site_Fourier_wave_vector_ loop_ _name '_atom_site_Fourier_wave_vector_x' '_atom_site_Fourier_wave_vector_y' '_atom_site_Fourier_wave_vector_z' _category atom_site_Fourier_wave_vector _type numb _list yes _list_reference '_atom_site_Fourier_wave_vector_seq_id' _enumeration_default 0.0 _definition ; Wave vectors of the Fourier terms used in the structural model to describe the atomic modulation functions, expressed with respect to the three-dimensional reciprocal basis that spans the lattice of main reflections. They are linear combinations with integer coefficients of the independent wave vectors given in the _cell_wave_vector_ list. Therefore, a generic Fourier wave vector is expressed as k=n(1)q(1)+...+n(p)q(p), where p is given by _cell_modulation_dimension. In the case of composites described in a single data block, these wave vectors are expressed with respect to the three-dimensional reciprocal basis of each subsystem (see _cell_subsystem_matrix_W_). ; ########################### ## ATOM_SITE_OCC_FOURIER ## ########################### data_atom_site_occ_Fourier_[] _name '_atom_site_occ_Fourier_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_occ_Fourier_id _atom_site_occ_Fourier_atom_site_label _atom_site_occ_Fourier_wave_vector_seq_id CuBr4_1 CuBr4 1 NC4_1_1 (NC4)1 1 NC4_2_1 (NC4)2 1 ; ; Example 1 - extracted from Madariaga, G., Z\'u\~niga, F.J., Paciorek, W.A. & Bocanegra, E.H. [Acta Cryst. (1990), B46, 620-628]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_OCC_FOURIER category record details about the Fourier components of the occupational modulation of the atom sites in a modulated structure. The (in general complex) coefficients of each Fourier component belong to the category ATOM_SITE_OCC_FOURIER_PARAM and are listed separately. ; data_atom_site_occ_Fourier_atom_site_label _name '_atom_site_occ_Fourier_atom_site_label' _category atom_site_occ_Fourier _type char _list yes _list_link_parent '_atom_site_label' _definition ; Modulation parameters are usually looped in separate lists. Modulated parameters are the atom positions (displacive modulation), the atomic occupation (occupational modulation) and/or the atomic anisotropic (or isotropic) displacement parameters (referred to as modulation of thermal parameters, since the term 'displacement parameters' is ambiguous in this context). _atom_site_occ_Fourier_atom_site_label is the code that identifies an atom in a loop in which the Fourier components of its occupational modulation are listed. This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_occ_Fourier_id _name '_atom_site_occ_Fourier_id' _category atom_site_occ_Fourier _type char _list yes _list_mandatory yes _list_link_child '_atom_site_occ_Fourier_param_id' _definition ; A code identifying each component of the occupational modulation of a given atom or rigid group when the modulation is expressed in terms of Fourier series. ; data_atom_site_occ_Fourier_wave_vector_seq_id _name '_atom_site_occ_Fourier_wave_vector_seq_id' _category atom_site_occ_Fourier _type numb _list yes _list_reference '_atom_site_occ_Fourier_id' _list_link_parent '_atom_site_Fourier_wave_vector_seq_id' _definition ; A numeric code identifying the wave vectors of the Fourier terms used in the structural model to describe the modulation functions corresponding to the occupational part of the distortion. This code must match _atom_site_Fourier_wave_vector_seq_id. ; ################################# ## ATOM_SITE_OCC_FOURIER_PARAM ## ################################# data_atom_site_occ_Fourier_param_[] _name '_atom_site_occ_Fourier_param_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_occ_Fourier_param_id _atom_site_occ_Fourier_param_modulus _atom_site_occ_Fourier_param_phase CuBr4_1 0.397(11) 0.392(6) NC4_1_1 0.216(42) -0.047(33) NC4_2_1 0.208(48) 0.132(27) ; ; Example 1 - extracted from Madariaga, G., Z\'u\~niga, F.J., Paciorek, W.A. & Bocanegra, E.H. [Acta Cryst. (1990), B46, 620-628]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_OCC_FOURIER_PARAM category record details about the coefficients of the Fourier series used to describe the occupational modulation of the atom sites in a modulated structure. The Fourier components are defined in the category ATOM_SITE_OCC_FOURIER and are listed separately. ; data_atom_site_occ_Fourier_param_cos _name '_atom_site_occ_Fourier_param_cos' _category atom_site_occ_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_occ_Fourier_param_id' _enumeration_default 0.0 _definition ; The occupational distortion of a given atom or rigid group is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Pc cos(2\p k r)+Ps sin(2\p k r), and the modulus-argument form, |P| cos(2\p k r+\d), where k is the wave vector of the term and r is the atomic average position. _atom_site_occ_Fourier_param_cos is the cosine coefficient (Pc) corresponding to the Fourier term defined by _atom_site_occ_Fourier_atom_site_label and _atom_site_occ_Fourier_wave_vector_seq_id. ; data_atom_site_occ_Fourier_param_id _name '_atom_site_occ_Fourier_param_id' _category atom_site_occ_Fourier_param _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_occ_Fourier_id' _definition ; A code identifying the (in general complex) coefficient of each term present in the Fourier series describing the occupational modulation of a given atom or rigid group. This code must match _atom_site_occ_Fourier_id. ; data_atom_site_occ_Fourier_param_modulus _name '_atom_site_occ_Fourier_param_modulus' _category atom_site_occ_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_occ_Fourier_param_id' _enumeration_range 0.0: _enumeration_default 0.0 _definition ; The occupational distortion of a given atom or rigid group is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Pc cos(2\p k r)+Ps sin(2\p k r), and the modulus-argument form, |P| cos(2\p k r+\d), where k is the wave vector of the term and r is the atomic average position. _atom_site_occ_Fourier_param_modulus is the modulus (|P|) of the complex amplitude corresponding to the Fourier term defined by _atom_site_occ_Fourier_atom_site_label and _atom_site_occ_Fourier_wave_vector_seq_id. ; data_atom_site_occ_Fourier_param_phase _name '_atom_site_occ_Fourier_param_phase' _category atom_site_occ_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_occ_Fourier_param_id' _enumeration_range -1.0:1.0 _enumeration_default 0.0 _units cy _units_detail 'Cycles' _definition ; The occupational distortion of a given atom or rigid group is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Pc cos(2\p k r)+Ps sin(2\p k r), and the modulus-argument form, |P| cos(2\p k r+\d), where k is the wave vector of the term and r is the atomic average position. _atom_site_occ_Fourier_param_phase is the phase (\d/2\p) in cycles corresponding to the Fourier term defined by _atom_site_occ_Fourier_atom_site_label and _atom_site_occ_Fourier_wave_vector_seq_id. ; data_atom_site_occ_Fourier_param_sin _name '_atom_site_occ_Fourier_param_sin' _category atom_site_occ_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_occ_Fourier_param_id' _enumeration_default 0.0 _definition ; The occupational distortion of a given atom or rigid group is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Pc cos(2\p k r)+Ps sin(2\p k r), and the modulus-argument form, |P| cos(2\p k r+\d), where k is the wave vector of the term and r is the atomic average position. _atom_site_occ_Fourier_param_sin is the sine coefficient (Ps) corresponding to the Fourier term defined by _atom_site_occ_Fourier_atom_site_label and _atom_site_occ_Fourier_wave_vector_seq_id. ; ###################### ## ATOM_SITE_PHASON ## ###################### data_atom_site_phason_[] _name '_atom_site_phason_[]' _category category_overview _type null # loop_ _example # _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - #; # No example #; #; #; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_PHASON category record details about the atomic phason correction. Although this kind of correction is intended to be overall, some refinement programs (for example, JANA2000) allow for this (theoretically dubious) atom-dependent phason treatment. ; data_atom_site_phason_atom_site_label _name '_atom_site_phason_atom_site_label' _category atom_site_phason _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_label' _definition ; The code that identifies an atom or rigid group in a loop in which the phason coefficients are listed. Although this kind of correction is intended to be overall, some refinement programs (for example, JANA2000) allow an independent phason correction for each atom or rigid group. In this case, _atom_site_phason_formula and _atom_site_phason_coeff should be used (see also _refine_ls_mod_overall_phason_). This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_phason_coeff _name '_atom_site_phason_coeff' _category atom_site_phason _type numb _type_conditions esd _list yes _list_reference '_atom_site_phason_atom_site_label' _enumeration_range 0.0: _enumeration_default 0.0 _definition ; The phason coefficient used to calculate (with the appropriate expression given in _atom_site_phason_formula) the atomic phason correction. Although this kind of correction is intended to be overall, some refinement programs (for example, JANA2000) allow an independent phason correction for each atom or rigid group. In this case, _atom_site_phason_formula and _atom_site_phason_coeff should be used (see also _refine_ls_mod_overall_phason_). ; data_atom_site_phason_formula _name '_atom_site_phason_formula' _category atom_site_phason _type char _list yes _list_reference '_atom_site_phason_atom_site_label' loop_ _enumeration _enumeration_detail 'Axe' 'Axe, J. D. (1980). Phys. Rev. B, 21, 4181-4190.' 'Ovr' 'Overhauser, A. W. (1971). Phys. Rev. B, 3, 3173-3182.' _definition ; The formula used for the phason correction. Although both kinds of corrections are intended to be overall, some refinement programs (for example, JANA2000) allow an independent phason correction for each atom or rigid group. In this case, _atom_site_phason_formula and _atom_site_phason_coeff should be used (see also _refine_ls_mod_overall_phason_). ; ########################### ## ATOM_SITE_ROT_FOURIER ## ########################### data_atom_site_rot_Fourier_[] _name '_atom_site_rot_Fourier_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_rot_Fourier_id _atom_site_rot_Fourier_atom_site_label _atom_site_rot_Fourier_axis _atom_site_rot_Fourier_wave_vector_seq_id SeO4_x_1 SeO4 x 1 SeO4_y_1 SeO4 y 1 ; ; Example 1 - example corresponding to the one-dimensional incommensurately modulated structure of K~2~SeO~4~. ; ; _atom_sites_rot_Fourier_axes_description ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; loop_ _atom_site_rot_Fourier_id _atom_site_rot_Fourier_atom_site_label _atom_site_rot_Fourier_axis _atom_site_rot_Fourier_wave_vector_seq_id Ph1_a1_1 Phenyl1 a1 1 Ph2_a1_1 Phenyl2 a1 1 Bph_a2_1 Biphenyl a2 1 ; ; Example 2 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. Note the entry from the ATOM_SITES_ROT_FOURIER category to describe collective information relating to all the atom sites. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_ROT_FOURIER category record details about the Fourier components present in the rotational part of the displacive modulation of a given rigid group. The translational part would appear in a separate list of items belonging to the ATOM_SITE_DISPLACE_FOURIER category. The (in general complex) coefficients of each Fourier component belong to the category ATOM_SITE_ROT_FOURIER_PARAM and are listed separately. ; data_atom_site_rot_Fourier_atom_site_label _name '_atom_site_rot_Fourier_atom_site_label' _category atom_site_rot_Fourier _type char _list yes _list_reference '_atom_site_rot_Fourier_id' _list_link_parent '_atom_site_label' _definition ; Modulation parameters are usually looped in separate lists. Modulated parameters are the atom positions (displacive modulation), the atomic occupation (occupational modulation) and/or the atomic anisotropic (or isotropic) displacement parameters (referred to as modulation of thermal parameters, since the term 'displacement parameters' is ambiguous in this context). _atom_site_rot_Fourier_atom_site_label is the code that identifies a rigid group in a loop in which the Fourier components of the rotational part of its displacive modulation are listed. The translational part (if any) would appear in a separate list (see _atom_site_displace_Fourier_atom_site_label). This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_rot_Fourier_axis _name '_atom_site_rot_Fourier_axis' _category atom_site_rot_Fourier _type char _list yes _list_reference '_atom_site_rot_Fourier_id' loop_ _enumeration _enumeration_detail x 'rotation around the a axis' y 'rotation around the b axis' z 'rotation around the c axis' a1 'rotation around an arbitrary a1 axis' a2 'rotation around an arbitrary a2 axis' a3 'rotation around an arbitrary a3 axis' _definition ; A label identifying the rotation component around a fixed point of a given rigid group whose modulation is being parameterized by Fourier series. a, b and c are the basic lattice vectors of the reference structure. For composites they refer to the reference structure of each subsystem. a~1~, a~2~ and a~3~ are defined by _atom_sites_rot_Fourier_axes_description. ; data_atom_site_rot_Fourier_id _name '_atom_site_rot_Fourier_id' _category atom_site_rot_Fourier _type char _list yes _list_mandatory yes _list_link_child '_atom_site_rot_Fourier_param_id' _definition ; A code identifying each component of the rotational modulation of a given rigid group when the modulation is expressed in terms of Fourier series. ; data_atom_site_rot_Fourier_wave_vector_seq_id _name '_atom_site_rot_Fourier_wave_vector_seq_id' _category atom_site_rot_Fourier _type numb _list yes _list_reference '_atom_site_rot_Fourier_id' _list_link_parent '_atom_site_Fourier_wave_vector_seq_id' _definition ; A numeric code identifying the wave vectors of the Fourier terms used in the structural model to describe the modulation functions corresponding to the rotational distortion of a rigid group. This code must match _atom_site_Fourier_wave_vector_seq_id. ; ################################# ## ATOM_SITE_ROT_FOURIER_PARAM ## ################################# data_atom_site_rot_Fourier_param_[] _name '_atom_site_rot_Fourier_param_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_rot_Fourier_param_id _atom_site_rot_Fourier_param_cos _atom_site_rot_Fourier_param_sin SeO4_x_1 -4.2(1) 0.91(3) SeO4_y_1 4.3(1) 0. ; ; Example 1 - example corresponding to the one-dimensional incommensurately modulated structure of K~2~SeO~4~. ; ; _atom_sites_rot_Fourier_axes_description ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; loop_ _atom_site_rot_Fourier_param_id _atom_site_rot_Fourier_param_modulus _atom_site_rot_Fourier_param_phase Ph1_a1_1 11.0(2) 0. Ph2_a1_1 11.0(2) 0.5 Bph_a2_1 1.0(1) 0.25 ; ; Example 2 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. Note the entry from the ATOM_SITES_ROT_FOURIER category to describe collective information relating to all the atom sites. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_ROT_FOURIER_PARAM category record details about the coefficients of the Fourier series used to describe the rotational component of the displacive modulation of a given rigid group. The translational part would appear in a separate list of items belonging to the ATOM_SITE_DISPLACE_FOURIER_PARAM category. The Fourier components are defined in the category ATOM_SITE_ROT_FOURIER and are listed separately. ; data_atom_site_rot_Fourier_param_cos _name '_atom_site_rot_Fourier_param_cos' _category atom_site_rot_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_rot_Fourier_param_id' _enumeration_default 0.0 _units 'deg' _units_detail 'Degrees' _definition ; The displacive distortion of a given rigid group is not completely described by _atom_site_displace_Fourier_. The rigid rotation of the group around a given axis passing through a fixed point (for example, the centre of mass of the group) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Rc cos(2\p k r)+Rs sin(2\p k r), and the modulus-argument form, |R| cos(2\p k r+\y), where k is the wave vector of the term and r is the atomic average position. _atom_site_rot_Fourier_param_cos is the cosine coefficient (Rc) in degrees corresponding to the Fourier term defined by _atom_site_rot_Fourier_atom_site_label, _atom_site_rot_Fourier_axis and _atom_site_rot_Fourier_wave_vector_seq_id. ; data_atom_site_rot_Fourier_param_id _name '_atom_site_rot_Fourier_param_id' _category atom_site_rot_Fourier_param _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_rot_Fourier_id' _definition ; A code identifying the (in general complex) coefficient of each term present in the Fourier series describing the rotational part of the displacive modulation of a given rigid group. This code must match _atom_site_rot_Fourier_id. ; data_atom_site_rot_Fourier_param_modulus _name '_atom_site_rot_Fourier_param_modulus' _category atom_site_rot_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_rot_Fourier_param_id' _enumeration_range 0.0: _enumeration_default 0.0 _units 'deg' _units_detail 'Degrees' _definition ; The displacive distortion of a given rigid group is not completely described by _atom_site_displace_Fourier_. The rigid rotation of the group around a given axis passing through a fixed point (for example, the centre of mass of the group) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Rc cos(2\p k r)+Rs sin(2\p k r), and the modulus-argument form, |R| cos(2\p k r+\y), where k is the wave vector of the term and r is the atomic average position. _atom_site_rot_Fourier_param_modulus is the modulus (|R|) in degrees of the complex amplitude corresponding to the Fourier term defined by _atom_site_rot_Fourier_atom_site_label, _atom_site_rot_Fourier_axis and _atom_site_rot_Fourier_wave_vector_seq_id. ; data_atom_site_rot_Fourier_param_phase _name '_atom_site_rot_Fourier_param_phase' _category atom_site_rot_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_rot_Fourier_param_id' _enumeration_range -1.0:1.0 _enumeration_default 0.0 _units cy _units_detail 'Cycles' _definition ; The displacive distortion of a given rigid group is not completely described by _atom_site_displace_Fourier_. The rigid rotation of the group around a given axis passing through a fixed point (for example, the centre of mass of the group) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Rc cos(2\p k r)+Rs sin(2\p k r), and the modulus-argument form, |R| cos(2\p k r+\y), where k is the wave vector of the term and r is the atomic average position. _atom_site_rot_Fourier_param_phase is the phase (\y/2\p) in cycles of the complex amplitude corresponding to the Fourier term defined by _atom_site_rot_Fourier_atom_site_label, _atom_site_rot_Fourier_axis and _atom_site_rot_Fourier_wave_vector_seq_id. ; data_atom_site_rot_Fourier_param_sin _name '_atom_site_rot_Fourier_param_sin' _category atom_site_rot_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_rot_Fourier_param_id' _enumeration_default 0.0 _units 'deg' _units_detail 'Degrees' _definition ; The displacive distortion of a given rigid group is not completely described by _atom_site_displace_Fourier_. The rigid rotation of the group around a given axis passing through a fixed point (for example, the centre of mass of the group) is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, Rc cos(2\p k r)+Rs sin(2\p k r), and the modulus-argument form, |R| cos(2\p k r+\y), where k is the wave vector of the term and r is the atomic average position. _atom_site_rot_Fourier_param_sin is the sine coefficient (Rs) in degrees corresponding to the Fourier term defined by _atom_site_rot_Fourier_atom_site_label, _atom_site_rot_Fourier_axis and _atom_site_rot_Fourier_wave_vector_seq_id. ; ######################### ## ATOM_SITE_U_FOURIER ## ######################### data_atom_site_U_Fourier_[] _name '_atom_site_U_Fourier_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_U_Fourier_id _atom_site_U_Fourier_atom_site_label _atom_site_U_Fourier_tens_elem _atom_site_U_Fourier_wave_vector_seq_id Mn_U11_2 Mn U11 2 Mn_U22_2 Mn U22 2 Mn_U33_2 Mn U33 2 Mn_U12_2 Mn U12 2 Mn_U13_2 Mn U13 2 Mn_U23_2 Mn U23 2 Cl1_U11_2 Cl1 U11 2 Cl1_U22_2 Cl1 U22 2 Cl1_U33_2 Cl1 U33 2 Cl1_U12_2 Cl1 U12 2 Cl1_U13_2 Cl1 U13 2 Cl1_U23_2 Cl1 U23 2 # - - - - data truncated for brevity - - - - ; ; Example 1 - extracted from Meyer, Paciorek, Schenk, Chapuis & Depmeier [Acta Cryst. (1994), B50, 333-343]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_U_FOURIER category record details about the Fourier components describing the modulation of the atomic thermal parameters in a modulated structure. ; data_atom_site_U_Fourier_atom_site_label _name '_atom_site_U_Fourier_atom_site_label' _category atom_site_U_Fourier _type char _list yes _list_reference '_atom_site_U_Fourier_id' _list_link_parent '_atom_site_label' _definition ; Modulation parameters are usually looped in separate lists. Modulated parameters are the atom positions (displacive modulation), the atomic occupation (occupational modulation) and/or the atomic anisotropic (or isotropic) displacement parameters (referred to as modulation of thermal parameters, since the term 'displacement parameters' is ambiguous in this context). _atom_site_U_Fourier_atom_site_label is the code that identifies an atom in a loop in which the Fourier components of its thermal-parameters modulation are listed. This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_U_Fourier_id _name '_atom_site_U_Fourier_id' _category atom_site_U_Fourier _type char _list yes _list_mandatory yes _list_link_child '_atom_site_U_Fourier_param_id' _definition ; A code identifying each Fourier component used to describe the modulation of the atomic thermal parameters. ; data_atom_site_U_Fourier_tens_elem _name '_atom_site_U_Fourier_tens_elem' _category atom_site_U_Fourier _type char _list yes _list_reference '_atom_site_U_Fourier_id' loop_ _enumeration _enumeration_detail U11 'modulation of U11' U12 'modulation of U12' U13 'modulation of U13' U22 'modulation of U22' U23 'modulation of U23' U33 'modulation of U33' Uiso 'modulation of U~isotropic~' _definition ; A label identifying the temperature tensor element U(ij) of a given atom or rigid group whose modulation is being parameterized by Fourier series. ; data_atom_site_U_Fourier_wave_vector_seq_id _name '_atom_site_U_Fourier_wave_vector_seq_id' _category atom_site_U_Fourier _type numb _list yes _list_reference '_atom_site_U_Fourier_id' _list_link_parent '_atom_site_Fourier_wave_vector_seq_id' _definition ; A numeric code identifying the wave vectors of the Fourier terms used to describe the modulation functions corresponding to the temperature factors of an atom or rigid group. This code must match _atom_site_Fourier_wave_vector_seq_id. ; ############################### ## ATOM_SITE_U_FOURIER_PARAM ## ############################### data_atom_site_U_Fourier_param_[] _name '_atom_site_U_Fourier_param_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _atom_site_U_Fourier_param_id _atom_site_U_Fourier_param_modulus _atom_site_U_Fourier_param_phase Mn_U11_2 0.003(3) 0.0 Mn_U22_2 0.0 0.0 Mn_U33_2 0.017(2) 0.0 Mn_U12_2 0.0 0.0 Mn_U13_2 0.00(2) 0.5 Mn_U23_2 0.0 0.0 Cl1_U11_2 0.003(3) 0.5 Cl1_U22_2 0.005(3) 0.0 Cl1_U33_2 0.020(3) 0.0 Cl1_U12_2 0.008(3) 0.0 Cl1_U13_2 0.02(2) 0.75 Cl1_U23_2 0.03(3) 0.25 # - - - - data truncated for brevity - - - - ; ; Example 1 - extracted from Meyer, Paciorek, Schenk, Chapuis & Depmeier [Acta Cryst. (1994), B50, 333-343]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_U_FOURIER category record details about the coefficients of the Fourier series used to describe the modulation of the atomic thermal parameters in a modulated structure. The Fourier components are defined in the category ATOM_SITE_U_FOURIER and are listed separately. ; data_atom_site_U_Fourier_param_cos _name '_atom_site_U_Fourier_param_cos' _category atom_site_U_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_U_Fourier_param_id' _enumeration_default 0.0 _units A^2^ _units_detail 'Angstroms squared' _definition ; The modulation of the atomic thermal parameters is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, U(ij)c cos(2\p k r)+U(ij)s sin(2\p k r), and the modulus-argument form, |U(ij)| cos(2\p k r+\c), where k is the wave vector of the term and r is the atomic average position. _atom_site_U_Fourier_param_cos is the cosine coefficient [U(ij)c], in angstroms squared, corresponding to the Fourier term defined by _atom_site_U_Fourier_atom_site_label, _atom_site_U_Fourier_tens_elem and _atom_site_U_Fourier_wave_vector_seq_id. ; data_atom_site_U_Fourier_param_id _name '_atom_site_U_Fourier_param_id' _category atom_site_U_Fourier_param _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_U_Fourier_id' _definition ; A code identifying the (in general complex) coefficient of each term present in the Fourier series describing the modulation of the atomic thermal parameters. This code must match _atom_site_U_Fourier_id. ; data_atom_site_U_Fourier_param_modulus _name '_atom_site_U_Fourier_param_modulus' _category atom_site_U_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_U_Fourier_param_id' _enumeration_range 0.0: _enumeration_default 0.0 _units A^2^ _units_detail 'Angstroms squared' _definition ; The modulation of the atomic thermal parameters is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, U(ij)c cos(2\p k r)+U(ij)s sin(2\p k r), and the modulus-argument form, |U(ij)| cos(2\p k r+\c), where k is the wave vector of the term and r is the atomic average position. _atom_site_U_Fourier_param_modulus is the modulus [|U(ij)|], in angstroms squared, of the complex amplitudes corresponding to the Fourier term defined by _atom_site_U_Fourier_atom_site_label, _atom_site_U_Fourier_tens_elem and _atom_site_U_Fourier_wave_vector_seq_id. ; data_atom_site_U_Fourier_param_phase _name '_atom_site_U_Fourier_param_phase' _category atom_site_U_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_U_Fourier_param_id' _enumeration_range -1.0:1.0 _enumeration_default 0.0 _units cy _units_detail 'Cycles' _definition ; The modulation of the atomic thermal parameters is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, U(ij)c cos(2\p k r)+U(ij)s sin(2\p k r), and the modulus-argument form, |U(ij)| cos(2\p k r+\c), where k is the wave vector of the term and r is the atomic average position. _atom_site_U_Fourier_param_phase is the phase (\c/2\p), in cycles, of the complex amplitude corresponding to the Fourier term defined by _atom_site_U_Fourier_atom_site_label, _atom_site_U_Fourier_tens_elem and _atom_site_U_Fourier_wave_vector_seq_id. ; data_atom_site_U_Fourier_param_sin _name '_atom_site_U_Fourier_param_sin' _category atom_site_U_Fourier_param _type numb _type_conditions esd _list yes _list_reference '_atom_site_U_Fourier_param_id' _enumeration_default 0.0 _units A^2^ _units_detail 'Angstroms squared' _definition ; The modulation of the atomic thermal parameters is usually parameterized by Fourier series. Each term of the series commonly adopts two different representations: the sine-cosine form, U(ij)c cos(2\p k r)+U(ij)s sin(2\p k r), and the modulus-argument form, |U(ij)| cos(2\p k r+\c), where k is the wave vector of the term and r is the atomic average position. _atom_site_U_Fourier_param_sin is the sine coefficient [U(ij)s], in angstroms squared, corresponding to the Fourier term defined by _atom_site_U_Fourier_atom_site_label, _atom_site_U_Fourier_tens_elem and _atom_site_U_Fourier_wave_vector_seq_id. ; ##################################### ## ATOM_SITE_DISPLACE_SPECIAL_FUNC ## ##################################### data_atom_site_displace_special_func_[] _name '_atom_site_displace_special_func_[]' _category category_overview _type null loop_ _example _example_detail ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # In this example the displacive modulation of the O(4) # atom was modelled using a sawtooth-shaped function. # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - loop_ _atom_site_displace_special_func_atom_site_label _atom_site_displace_special_func_sawtooth_ax _atom_site_displace_special_func_sawtooth_ay _atom_site_displace_special_func_sawtooth_az _atom_site_displace_special_func_sawtooth_c _atom_site_displace_special_func_sawtooth_w O(4) -0.270(6) 0.022(9) 0.014(2) 0.42(2) 1.07(2) ; ; Example 1 - extracted from Gao, Coppens, Cox & Moodenbaugh [Acta Cryst. (1993), A49, 141-148]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_DISPLACE_SPECIAL_FUNC category record details about the displacive modulation of an atom site in a modulated structure when it is not described by Fourier series. Special functions are effective in some cases where the modulations are highly anharmonic, since the number of parameters is drastically reduced. However, they are in general discontinuous or with discontinuous derivatives and therefore these functions describe an ideal situation that never occurs in a real modulated crystal. Up to now, only a few types of special functions have been used and all of them come from the JANA suite of programs. Although this approach is far from being general, it has the advantage that the functions are tightly defined and therefore the atomic displacements and occupations can be calculated easily. In this dictionary, only the special functions available in JANA2000 have been included. These are: (1) Sawtooth functions for atomic displacive modulation along x, y and z. (2) Crenel functions for the occupational modulation of atoms and rigid groups. Both of these only apply to one-dimensional modulated structures. ; data_atom_site_displace_special_func_atom_site_label _name '_atom_site_displace_special_func_atom_site_label' _category atom_site_displace_special_func _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_label' _definition ; The code that identifies an atom in a loop in which the special function that describes its displacive modulation is being defined. This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_displace_special_func_sawtooth_ loop_ _name '_atom_site_displace_special_func_sawtooth_ax' '_atom_site_displace_special_func_sawtooth_ay' '_atom_site_displace_special_func_sawtooth_az' '_atom_site_displace_special_func_sawtooth_c' '_atom_site_displace_special_func_sawtooth_w' _category atom_site_displace_special_func _type numb _type_conditions esd _list yes _list_reference '_atom_site_displace_special_func_atom_site_label' _enumeration_default 0.0 _definition ; _atom_site_displace_special_func_sawtooth_ items are the adjustable parameters of a sawtooth function. A displacive sawtooth function along the internal space is defined as follows: ux=2*ax[(x4-c)/w] uy=2*ay[(x4-c)/w] uz=2*az[(x4-c)/w] for x4 belonging to the interval [c-(w/2), c+(w/2)], where ax, ay and az are the amplitudes (maximum displacements) along each crystallographic axis, w is its width, x4 is the internal coordinate and c is the centre of the function in internal space. ux, uy and uz must be expressed in relative units. The use of this function is restricted to one-dimensional modulated structures. For more details, see the manual for JANA2000 (Petricek & Dusek, 2000). Reference: Petricek, V. & Dusek, M. (2000). JANA2000. The crystallographic computing system. Institute of Physics, Prague, Czech Republic. ; ################################ ## ATOM_SITE_OCC_SPECIAL_FUNC ## ################################ data_atom_site_occ_special_func_[] _name '_atom_site_occ_special_func_[]' _category category_overview _type null loop_ _example _example_detail ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # In this example the occupational modulation of the Mn(2) # atom was modelled using a square-wave crenel function. # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - loop_ _atom_site_occ_special_func_atom_site_label _atom_site_occ_special_func_crenel_c _atom_site_occ_special_func_crenel_w Mn(2) 0.25 0.623(4) ; ; Example 1 - extracted from Elding-Pont\'en, M., Stenberg, L., Lidin, S., Madariaga, G. & P\'erez-Mato, J.M. [Acta Cryst. (1997), B53, 364-372]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITE_DISPLACE_OCC_SPECIAL_FUNC category record details about the occupational modulation of a given atom or rigid group in a modulated structure when it is not described by Fourier series. Special functions are effective in some cases where the modulations are highly anharmonic, since the number of parameters is drastically reduced. However, they are in general discontinuous or with discontinuous derivatives and therefore these functions describe an ideal situation that never occurs in a real modulated crystal. Up to now, only a few types of special functions have been used and all of them come from the JANA suite of programs. Although this approach is far from being general, it has the advantage that the functions are tightly defined and therefore the atomic displacements and occupations can be calculated easily. In this dictionary, only the special functions available in JANA2000 have been included. These are: (1) Sawtooth functions for atomic displacive modulation along x, y and z. (2) Crenel functions for the occupational modulation of atoms and rigid groups. Both of these only apply to one-dimensional modulated structures. ; data_atom_site_occ_special_func_atom_site_label _name '_atom_site_occ_special_func_atom_site_label' _category atom_site_occ_special_func _type char _list yes _list_mandatory yes _list_link_parent '_atom_site_label' _definition ; The code that identifies an atom or rigid group in a loop in which the parameters of the special function that describes its occupational modulation are listed. This code must match the _atom_site_label of the associated coordinate list and conform to the rules described in _atom_site_label. ; data_atom_site_occ_special_func_crenel_ loop_ _name '_atom_site_occ_special_func_crenel_c' '_atom_site_occ_special_func_crenel_w' _category atom_site_occ_special_func _type numb _type_conditions esd _list yes _list_reference '_atom_site_occ_special_func_atom_site_label' _enumeration_default 0.0 _definition ; _atom_site_occ_special_func_crenel_ items are the adjustable parameters of a crenel function. An occupational crenel function along the internal space is defined as follows: p(x4)=1 if x4 belongs to the interval [c-w/2,c+w/2] p(x4)=0 if x4 is outside the interval [c-w/2,c+w/2], where x4 is the internal coordinate, c is the centre of the function in internal space and w is its width. The use of this function is restricted to one-dimensional modulated structures. For more details, see the manual for JANA2000 (Petricek & Dusek, 2000). Reference: Petricek, V. & Dusek, M. (2000). JANA2000. The crystallographic computing system. Institute of Physics, Prague, Czech Republic. ; ################################# ## ATOM_SITES_DISPLACE_FOURIER ## ################################# data_atom_sites_displace_Fourier_[] _name '_atom_sites_displace_Fourier_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _atom_sites_displace_Fourier_axes_description ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; ; ; Example 1 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITES_DISPLACE_FOURIER category record details common to the displacive modulation of atom sites in a modulated structure. Details for individual atom sites are described by data items in the ATOM_SITE_DISPLACE_FOURIER category. ; data_atom_sites_displace_Fourier_axes_description _name '_atom_sites_displace_Fourier_axes_description' _category atom_sites_displace_Fourier _type char _example ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; _definition ; The definition of the axes used for describing the displacive modulation, parameterized by Fourier series, when they are other than the crystallographic axes. ; ########################### ## ATOM_SITES_MODULATION ## ########################### data_atom_sites_modulation_[] _name '_atom_sites_modulation_[]' _category category_overview _type null # loop_ _example # _example_detail # # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # ; # No example # ; # ; # ; # # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITES_MODULATION category record details common to the modulation of atom sites in a modulated structure. ; data_atom_sites_modulation_global_phase_t_ loop_ _name '_atom_sites_modulation_global_phase_t_1' '_atom_sites_modulation_global_phase_t_2' '_atom_sites_modulation_global_phase_t_3' '_atom_sites_modulation_global_phase_t_4' '_atom_sites_modulation_global_phase_t_5' '_atom_sites_modulation_global_phase_t_6' '_atom_sites_modulation_global_phase_t_7' '_atom_sites_modulation_global_phase_t_8' _category atom_sites_modulation _type numb _enumeration_range -1.0:1.0 _enumeration_default 0.0 _units cy _units_detail 'Cycles' _definition ; The initial phases, in cycles, of the modulation waves. For incommensurate structures they are irrelevant. However, they are essential for the description of commensurate structures within the superspace formalism, since they determine the space group of the commensurate superstructure [see Perez-Mato, Madariaga, Zu\~niga & Garcia Arribas (1987) or van Smaalen (1995)]. Note that for composites described using a single data block, the initial phases for each subsystem are derived using the W matrices (see _cell_subsystem_matrix_W_) from a unique set of global phases whose values are assigned to _atom_sites_modulation_global_phase_t_. Detailed information can be found in van Smaalen (1995). Ref: Perez-Mato, J. M., Madariaga, G., Zu\~niga, F. J. & Garcia Arribas, A. (1987). Acta Cryst. A43, 216-226. Smaalen, S. van (1995). Crystallogr. Rev. 4, 79-202. ; ############################ ## ATOM_SITES_ROT_FOURIER ## ############################ data_atom_sites_rot_Fourier_[] _name '_atom_sites_rot_Fourier_[]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _atom_sites_rot_Fourier_axes_description ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; ; ; Example 1 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the ATOM_SITES_ROT_FOURIER category record details about the rotational component of the displacive modulation of a given rigid group as a whole. Details for individual atom sites are described by data items in the ATOM_SITES_ROT_FOURIER category. ; data_atom_sites_rot_Fourier_axes_description _name '_atom_sites_rot_Fourier_axes_description' _category atom_sites_rot_Fourier _type char _example ; a1 and a2 are respectively the long molecular axis and the axis normal to the mean molecular plane. ; _definition ; The definition of the axes used for describing the rotational part of the displacive modulation of a given rigid group, parameterized by Fourier series, when they are other than the crystallographic axes. ; ################ ## AUDIT_LINK ## ################ data_audit_link_[ms] _name '_audit_link_[ms]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _audit_link_block_code _audit_link_block_description . 'publication details' K2SEO4_COM 'experimental data common to ref./mod. structures' K2SEO4_REFRNCE 'reference structure' K2SEO4_MOD 'modulated structure' ; ; Example 1 - example file for the one-dimensional incommensurately modulated structure of K~2~SeO~4~. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _audit_link_block_code 'PbSVS2_MOD_VS2' ; ; Example 2 - example with a trailing string referencing a modulated structure of the subsystem labelled by _cell_subsystem_code. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; This category description does NOT introduce a new category; instead, it describes the recommended practice for using block codes as described in the core AUDIT_LINK category for descriptions of modulated structures. The value of _audit_block_code may be associated with a data block in the same file or in a different file related to the current data block. The value of _audit_block_code should be unique. It is recommended that data blocks are named as follows: The name of the data block containing those items that, for a particular material, are independent of the specific structure (modulated, reference etc.). For example, the experimental set-up or publication details would be described here. _REFRNCE The name of the data block that contains specific details of the reference (unmodulated) structure if it was refined separately using only main reflections. In the case of composites, this data block may contain those items that are common to the reference structures of all subsystems. _MOD The name of the data block in which specific details of the modulated structure are given. In the case of composites, this data block may include either those items that are common to the modulated structures of all subsystems or the whole modulated structure if it is described implicitly through the *_subsystem_code pointers. A trailing code following the reserved words MOD or REFRNCE indicates that the corresponding data block includes structural information corresponding to the modulated or reference structures of the subsystem labelled by _cell_subsystem_code. A recommended format for is given in the definitions of _pd_block_[pd] and _pd_block_id in the dictionary extension cif_pd.dic (http://www.iucr.org/cif/pd/index.html). ; ########## ## CELL ## ########## data_cell[ms] _name '_cell_[ms]' _category category_overview _type null _definition ; Data items in the CELL category record details about the crystallographic cell parameters and their measurement. This category is already defined in the core CIF dictionary but is extended in this dictionary by the addition of some items that are specific for modulated and composite structures. ; data_cell_modulation_dimension _name '_cell_modulation_dimension' _category cell _type numb _enumeration_range 1:8 _definition ; Number of additional reciprocal vectors needed to index the whole diffraction pattern using integer Miller indices. ; data_cell_reciprocal_basis_description _name '_cell_reciprocal_basis_description' _category cell _type char loop_ _example _example_detail ; a*,b*,c* (reciprocal basis spanning the lattice of main reflections) and q (incommensurate with respect to a*,b*,c*) ; ; Typical choice for a one-dimensional incommensurate structure. ; ; The diffraction pattern can be indexed with four integers based on the reciprocal vectors a*~1~=a*~11~, a*~2~=a*~12~, a*~3~=a*~13~, a*~4~=a*~21~. a*~1j~ (j=1,2,3) index the main reflections of the 1st subsystem. a*~21~ is incommensurate with a*~11~. ; ; Common choice for a misfit layer compound composed of two subsystems that have in common two reciprocal vectors. Extracted from van Smaalen [Crystallogr. Rev. (1995), 4, 79-202]. ; _definition ; Definition of the higher-dimensional basis with respect to which the Miller indices are defined. The three-dimensional basis used to index the additional wave vectors should be clearly indicated. ; #data_cell_reciprocal_basis_vect_number # _name '_cell_reciprocal_basis_vect_number' # _category cell # _type numb # _enumeration_range 4:11 # _definition #; Minimal number of reciprocal vectors spanning the higher- # dimensional reciprocal basis. Their number must match # _cell_modulation_dimension + 3. #; #################### ## CELL_SUBSYSTEM ## #################### data_cell_subsystem_[ms] _name '_cell_subsystem_[ms]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _cell_subsystems_number 2 loop_ _cell_subsystem_code _cell_subsystem_description _cell_subsystem_matrix_W_1_1 _cell_subsystem_matrix_W_1_4 _cell_subsystem_matrix_W_2_2 _cell_subsystem_matrix_W_3_3 _cell_subsystem_matrix_W_4_1 _cell_subsystem_matrix_W_4_4 NbS2 '1st subsystem' 1 0 1 1 0 1 LaS '2nd subsystem' 0 1 1 1 1 0 ; ; Example 1 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the CELL_SUBSYSTEM category record details about the crystallographic cell parameters of each subsystem present in a composite. ; data_cell_subsystem_code _name '_cell_subsystem_code' _category cell_subsystem _type char _list yes _example 'NbS2' _definition ; The code identifying uniquely a certain composite subsystem. This code is used to identify the data blocks that contain the structural information associated with the subsystem. ; data_cell_subsystem_description _name '_cell_subsystem_description' _category cell_subsystem _type char _list yes _example 'NbS2 part of the layer compound (LaS)~1.14~NbS~2~' _definition ; Description of each subsystem defining a composite structurally. The number of definitions must match the number given in _cell_subsystems_number. ; data_cell_subsystem_matrix_W_ loop_ _name '_cell_subsystem_matrix_W_1_1' '_cell_subsystem_matrix_W_1_2' '_cell_subsystem_matrix_W_1_3' '_cell_subsystem_matrix_W_1_4' '_cell_subsystem_matrix_W_1_5' '_cell_subsystem_matrix_W_1_6' '_cell_subsystem_matrix_W_1_7' '_cell_subsystem_matrix_W_1_8' '_cell_subsystem_matrix_W_1_9' '_cell_subsystem_matrix_W_1_10' '_cell_subsystem_matrix_W_1_11' '_cell_subsystem_matrix_W_2_1' '_cell_subsystem_matrix_W_2_2' '_cell_subsystem_matrix_W_2_3' '_cell_subsystem_matrix_W_2_4' '_cell_subsystem_matrix_W_2_5' '_cell_subsystem_matrix_W_2_6' '_cell_subsystem_matrix_W_2_7' '_cell_subsystem_matrix_W_2_8' '_cell_subsystem_matrix_W_2_9' '_cell_subsystem_matrix_W_2_10' '_cell_subsystem_matrix_W_2_11' '_cell_subsystem_matrix_W_3_1' '_cell_subsystem_matrix_W_3_2' '_cell_subsystem_matrix_W_3_3' '_cell_subsystem_matrix_W_3_4' '_cell_subsystem_matrix_W_3_5' '_cell_subsystem_matrix_W_3_6' '_cell_subsystem_matrix_W_3_7' '_cell_subsystem_matrix_W_3_8' '_cell_subsystem_matrix_W_3_9' '_cell_subsystem_matrix_W_3_10' '_cell_subsystem_matrix_W_3_11' '_cell_subsystem_matrix_W_4_1' '_cell_subsystem_matrix_W_4_2' '_cell_subsystem_matrix_W_4_3' '_cell_subsystem_matrix_W_4_4' '_cell_subsystem_matrix_W_4_5' '_cell_subsystem_matrix_W_4_6' '_cell_subsystem_matrix_W_4_7' '_cell_subsystem_matrix_W_4_8' '_cell_subsystem_matrix_W_4_9' '_cell_subsystem_matrix_W_4_10' '_cell_subsystem_matrix_W_4_11' '_cell_subsystem_matrix_W_5_1' '_cell_subsystem_matrix_W_5_2' '_cell_subsystem_matrix_W_5_3' '_cell_subsystem_matrix_W_5_4' '_cell_subsystem_matrix_W_5_5' '_cell_subsystem_matrix_W_5_6' '_cell_subsystem_matrix_W_5_7' '_cell_subsystem_matrix_W_5_8' '_cell_subsystem_matrix_W_5_9' '_cell_subsystem_matrix_W_5_10' '_cell_subsystem_matrix_W_5_11' '_cell_subsystem_matrix_W_6_1' '_cell_subsystem_matrix_W_6_2' '_cell_subsystem_matrix_W_6_3' '_cell_subsystem_matrix_W_6_4' '_cell_subsystem_matrix_W_6_5' '_cell_subsystem_matrix_W_6_6' '_cell_subsystem_matrix_W_6_7' '_cell_subsystem_matrix_W_6_8' '_cell_subsystem_matrix_W_6_9' '_cell_subsystem_matrix_W_6_10' '_cell_subsystem_matrix_W_6_11' '_cell_subsystem_matrix_W_7_1' '_cell_subsystem_matrix_W_7_2' '_cell_subsystem_matrix_W_7_3' '_cell_subsystem_matrix_W_7_4' '_cell_subsystem_matrix_W_7_5' '_cell_subsystem_matrix_W_7_6' '_cell_subsystem_matrix_W_7_7' '_cell_subsystem_matrix_W_7_8' '_cell_subsystem_matrix_W_7_9' '_cell_subsystem_matrix_W_7_10' '_cell_subsystem_matrix_W_7_11' '_cell_subsystem_matrix_W_8_1' '_cell_subsystem_matrix_W_8_2' '_cell_subsystem_matrix_W_8_3' '_cell_subsystem_matrix_W_8_4' '_cell_subsystem_matrix_W_8_5' '_cell_subsystem_matrix_W_8_6' '_cell_subsystem_matrix_W_8_7' '_cell_subsystem_matrix_W_8_8' '_cell_subsystem_matrix_W_8_9' '_cell_subsystem_matrix_W_8_10' '_cell_subsystem_matrix_W_8_11' '_cell_subsystem_matrix_W_9_1' '_cell_subsystem_matrix_W_9_2' '_cell_subsystem_matrix_W_9_3' '_cell_subsystem_matrix_W_9_4' '_cell_subsystem_matrix_W_9_5' '_cell_subsystem_matrix_W_9_6' '_cell_subsystem_matrix_W_9_7' '_cell_subsystem_matrix_W_9_8' '_cell_subsystem_matrix_W_9_9' '_cell_subsystem_matrix_W_9_10' '_cell_subsystem_matrix_W_9_11' '_cell_subsystem_matrix_W_10_1' '_cell_subsystem_matrix_W_10_2' '_cell_subsystem_matrix_W_10_3' '_cell_subsystem_matrix_W_10_4' '_cell_subsystem_matrix_W_10_5' '_cell_subsystem_matrix_W_10_6' '_cell_subsystem_matrix_W_10_7' '_cell_subsystem_matrix_W_10_8' '_cell_subsystem_matrix_W_10_9' '_cell_subsystem_matrix_W_10_10' '_cell_subsystem_matrix_W_10_11' '_cell_subsystem_matrix_W_11_1' '_cell_subsystem_matrix_W_11_2' '_cell_subsystem_matrix_W_11_3' '_cell_subsystem_matrix_W_11_4' '_cell_subsystem_matrix_W_11_5' '_cell_subsystem_matrix_W_11_6' '_cell_subsystem_matrix_W_11_7' '_cell_subsystem_matrix_W_11_8' '_cell_subsystem_matrix_W_11_9' '_cell_subsystem_matrix_W_11_10' '_cell_subsystem_matrix_W_11_11' _category cell_subsystem _type numb # _type_construct '( *-?[0-9]+)' _list yes _list_reference '_cell_subsystem_code' _enumeration_default 0 _definition ; In the case of composites, for each subsystem the matrix W as defined in van Smaalen (1991); see also van Smaalen (1995). Its dimension must match (_cell_modulation_dimension+3)*(_cell_modulation_dimension+3). Intergrowth compounds are composed of several periodic substructures in which the reciprocal lattices of two different subsystems are incommensurate in at least one direction. The indexing of the whole diffraction diagram with integer indices requires more than three reciprocal basic vectors. However, the distinction between main reflections and satellites is not as obvious as in normal incommensurate structures. Indeed, true satellites are normally difficult to locate for composites and the modulation wave vectors are reciprocal vectors of the other subsystem(s) referred to the reciprocal basis of one of them. The choice of the enlarged reciprocal basis {a*, b*, c*, q~1~,..., q~d~} is completely arbitrary, but the reciprocal basis of each subsystem is always known through the W matrices. These matrices [(3+d)x(3+d)-dimensional], one for each subsystem, can be blocked as follows: (Z^\n^~3~ Z^\n^~d~) W^\n^= ( ) (V^\n^~3~ V^\n^~d~), the dimension of each block being (3x3), (3xd), (dx3) and (dxd) for Z^\n^~3~, Z^\n^~d~, V^\n^~3~ and V^\n^~d~, respectively. For example, Z^\n^ expresses the reciprocal basis of each subsystem in terms of the basis {a*, b*, c*, q~1~ ,..., q~d~}. W^\n^ also gives the irrational components of the modulation wave vectors of each subsystem in its own three-dimensional reciprocal basis {a~\n~*, b~\n~*, c~\n~*} and the superspace group of a given subsystem from the unique superspace group of the composite. The structure of these materials is always described by a set of incommensurate structures, one for each subsystem. The atomic coordinates, modulation parameters and wave vectors used for describing the modulation(s) are always referred to the (direct or reciprocal) basis of each particular subsystem. Although expressing the structural results in the chosen common basis is possible (using the matrices W), it is less confusing to use this alternative description. Atomic coordinates are only referred to a common basis when interatomic distances are calculated. Usually, the reciprocal vectors {a*, b* and c*} span the lattice of main reflections of one of the subsystems and therefore its W matrix is the unit matrix. For composites described in a single data block using *_subsystem_code pointers, the cell parameters, the superspace group and the measured modulation wave vectors (see CELL_WAVE_VECTOR below) correspond to the reciprocal basis described in _cell_reciprocal_basis_description and coincide with the reciprocal basis of the specific subsystem (if any) whose W matrix is the unit matrix. The cell parameters and the symmetry of the remaining subsystems can be derived using the appropriate W matrices. In any case (single or multiblock CIF), the values assigned to the items describing the atomic parameters (including the wave vectors used to describe the modulations) are always the same and are referred to the basis of each particular subsystem. Such a basis will be explicitly given in a multiblock CIF or should be calculated (with the appropriate W matrix) in the case of a single block description of the composite. Ref: Smaalen, S. van (1991). Phys. Rev. B, 43, 11330-11341. Smaalen, S. van (1995). Crystallogr. Rev. 4, 79-202. ; ##################### ## CELL_SUBSYSTEMS ## ##################### data_cell_subsystems_[ms] _name '_cell_subsystems_[ms]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _cell_subsystems_number 2 ; ; Example 1 - based on the modulated structure of inorganic misfit layer (LaS)~1.14~NbS~2~ [Smaalen, S. van (1991). J. Phys. Condens. Matter, 3, 1247-1263]. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the CELL_SUBSYSTEMS category describe the gross structure of the subsystems present in a composite. ; data_cell_subsystems_number _name '_cell_subsystems_number' _category cell_subsystems _type numb _enumeration_range 2: _definition ; The number of subsystems used to define the structural model of a composite structure. ; ###################### ## CELL_WAVE_VECTOR ## ###################### data_cell_wave_vector_[ms] _name '_cell_wave_vector_[ms]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _cell_wave_vector_seq_id _cell_wave_vector_x 1 0.318(5) ; ; Example 1 - example corresponding to the one-dimensional incommensurately modulated structure of K~2~SeO~4~. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the CELL_WAVE_VECTOR category list the independent modulation wave vectors q~i~. The diffraction vectors are indexed in the form ha*+kb*+lc*+sum~i~ (m~i~q~i~). sum~i~ is taken over all wave vectors. In this version of the dictionary, the index i has been restricted to be less than 9. ; data_cell_wave_vector_seq_id _name '_cell_wave_vector_seq_id' _category cell_wave_vector _type numb # _type_construct [1-('_cell_modulation_dimension')] _list yes _definition ; A numeric code to identify each independent wave vector. These codes define uniquely the reciprocal basis and, therefore, force the order of the Miller indices assigned to intensities, crystal faces etc. ; data_cell_wave_vector_ loop_ _name '_cell_wave_vector_x' '_cell_wave_vector_y' '_cell_wave_vector_z' _category cell_wave_vector _type numb _type_conditions esd _list yes _list_reference '_cell_wave_vector_seq_id' _enumeration_default 0.0 _definition ; Independent modulation wave vector(s) with which the whole diffraction pattern is indexed, expressed as fractions of the three reciprocal basis vectors of the reference structure. In the case of composites, the modulation wave vectors of each subsystem are expressed in terms of the reciprocal basis of its corresponding reference structure. Their number must match _cell_modulation_dimension. In the case of composites described in a single data block, the wave vectors are expressed in the three-dimensional basis chosen as reference in _cell_reciprocal_basis_description, which would correspond to the subsystem (if any) whose W matrix is the {(_cell_modulation_dimension + 3)* (_cell_modulation_dimension + 3)} unit matrix. In this case, the wave vectors used to describe the modulation of each subsystem are referred to their own reciprocal basis via the W matrices (for details see _cell_subsystem_matrix_W_ and _atom_site_Fourier_wave_vector_). ; ####################### ## CELL_WAVE_VECTORS ## ####################### data_cell_wave_vectors_[ms] _name '_cell_wave_vectors_[ms]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; _cell_wave_vectors_meas_details 'Determined from profiles along q' ; ; Example 1 - example corresponding to the one-dimensional incommensurately modulated structure of K~2~SeO~4~. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; Data items in the CELL_WAVE_VECTORS category record details about the set of independent modulation wave vectors q~i~ and their measurement. The diffraction vectors are indexed in the form ha*+kb*+lc*+sum~i~ (m~i~q~i~). sum~i~ is taken over all wave vectors. In this version of the dictionary, the index i has been restricted to be less than 9. ; data_cell_wave_vectors_meas_details _name '_cell_wave_vectors_meas_details' _category cell_wave_vectors _type char _definition ; Details about the method used to determine the independent modulation wave vector(s). ; data_cell_wave_vectors_pressure_ loop_ _name '_cell_wave_vectors_pressure_max' '_cell_wave_vectors_pressure_min' _category cell_wave_vectors _type numb _type_conditions esd _units kPa _units_detail 'Kilopascals' _enumeration_range 0.0: _definition ; The maximum and minimum values of the pressure in kilopascals defining the interval within which the modulation wave vector(s) were measured. ; data_cell_wave_vectors_temp_ loop_ _name '_cell_wave_vectors_temp_max' '_cell_wave_vectors_temp_min' _category cell_wave_vectors _type numb _type_conditions esd _units K _units_detail 'Kelvins' _enumeration_range 0.0: _definition ; The maximum and minimum values of the temperature in kelvins defining the interval within which the modulation wave vector(s) were measured. ; data_cell_wave_vectors_variation _name '_cell_wave_vectors_variation' _category cell_wave_vectors _type char _definition ; Details concerning the behaviour (and its experimental detection) of the wave vector(s) with temperature and/or pressure within the ranges specified by _cell_wave_vectors_pressure_max, _cell_wave_vectors_pressure_min, _cell_wave_vectors_temp_max and _cell_wave_vectors_temp_min. ; ################## ## DIFFRN_REFLN ## ################## data_diffrn_refln[ms] _name '_diffrn_refln_[ms]' _category category_overview _type null _definition ; Data items in the DIFFRN_REFLN category record details about the intensities measured in the diffraction experiment. The DIFFRN_REFLN data items refer to individual intensity measurements and must be included in looped lists. (The DIFFRN_REFLNS data items specify the parameters that apply to all intensity measurements. The DIFFRN_REFLNS data items are not looped.) Data items in this category are extensions of the core CIF dictionary definitions to the indexing of diffraction intensities by higher-dimensional components. ; data_diffrn_refln_index_m_ loop_ _name '_diffrn_refln_index_m_1' '_diffrn_refln_index_m_2' '_diffrn_refln_index_m_3' '_diffrn_refln_index_m_4' '_diffrn_refln_index_m_5' '_diffrn_refln_index_m_6' '_diffrn_refln_index_m_7' '_diffrn_refln_index_m_8' _category diffrn_refln _type numb # _type_construct '( *-?[0-9]+)' _list yes loop_ _list_reference '_diffrn_refln_index_h' '_diffrn_refln_index_k' '_diffrn_refln_index_l' _definition ; Additional Miller indices needed to write the reciprocal vector of a certain reflection in the basis described in _cell_reciprocal_basis_description. Following the usual convention, such a vector would be expressed as H=h*a*+k*b*+l*c*+m1*q(1)+...+m8*q(8), where h,k,l are the usual _diffrn_refln_index_, and q(1)...q(8) represent the independent wave vectors given by _cell_wave_vector_ and identified by _cell_wave_vector_seq_id. Therefore, the total number of indices of a given reflection must match (_cell_modulation_dimension + 3) and the order of the additional indices must be consistent with the codes given in _cell_wave_vector_seq_id. These indices need not match _refln_index_m_ values if a transformation of the original measured cell has occurred. ; ################### ## DIFFRN_REFLNS ## ################### data_diffrn_reflns[ms] _name '_diffrn_reflns_[ms]' _category category_overview _type null _definition ; Data items in the DIFFRN_REFLNS category record details about the set of intensities measured in the diffraction experiment. The DIFFRN_REFLNS data items specify the parameters that apply to all intensity measurements. The DIFFRN_REFLNS data items are not looped. (The DIFFRN_REFLN data items refer to individual intensity measurements and must be included in looped lists.) Data items in this category extend the core CIF dictionary definitions providing independent checks on the range of values recorded for each of the additional Miller indices given in the DIFFRN_REFLN category. ; data_diffrn_reflns_limit_index_m_ loop_ _name '_diffrn_reflns_limit_index_m_1_max' '_diffrn_reflns_limit_index_m_1_min' '_diffrn_reflns_limit_index_m_2_max' '_diffrn_reflns_limit_index_m_2_min' '_diffrn_reflns_limit_index_m_3_max' '_diffrn_reflns_limit_index_m_3_min' '_diffrn_reflns_limit_index_m_4_max' '_diffrn_reflns_limit_index_m_4_min' '_diffrn_reflns_limit_index_m_5_max' '_diffrn_reflns_limit_index_m_5_min' '_diffrn_reflns_limit_index_m_6_max' '_diffrn_reflns_limit_index_m_6_min' '_diffrn_reflns_limit_index_m_7_max' '_diffrn_reflns_limit_index_m_7_min' '_diffrn_reflns_limit_index_m_8_max' '_diffrn_reflns_limit_index_m_8_min' _category diffrn_reflns _type numb # _type_construct '( *-?[0-9]+)' _definition ; Maximum and minimum values of the additional Miller indices appearing in _diffrn_refln_index_m_. The number of ranges must match _cell_modulation_dimension. The order of the additional indices must be consistent with the codes given in _cell_wave_vector_seq_id. ; data_diffrn_reflns_satellite_order_max _name '_diffrn_reflns_satellite_order_max' _category diffrn_reflns _type numb _definition ; Maximum order of observed satellites. ; ########################### ## DIFFRN_STANDARD_REFLN ## ########################### data_diffrn_standard_refln[ms] _name '_diffrn_standard_refln_[ms]' _category category_overview _type null _definition ; Data items in the DIFFRN_STANDARD_REFLN category record details about the reflections treated as standards during the measurement of diffraction intensities. Note that these are the individual standard reflections, not the results of the analysis of the standard reflections. Data items in this category are extensions of the core CIF dictionary definitions to the indexing of standard reflections by higher-dimensional components. ; data_diffrn_standard_refln_index_m_ loop_ _name '_diffrn_standard_refln_index_m_1' '_diffrn_standard_refln_index_m_2' '_diffrn_standard_refln_index_m_3' '_diffrn_standard_refln_index_m_4' '_diffrn_standard_refln_index_m_5' '_diffrn_standard_refln_index_m_6' '_diffrn_standard_refln_index_m_7' '_diffrn_standard_refln_index_m_8' _category diffrn_standard_refln _type numb # _type_construct '( *-?[0-9]+)' _list yes loop_ _list_reference '_diffrn_standard_refln_index_h' '_diffrn_standard_refln_index_k' '_diffrn_standard_refln_index_l' _definition ; Additional Miller indices needed to write the reciprocal vectors of the standard intensities used in the diffraction measurement process, in the basis described in _cell_reciprocal_basis_description. The total number of indices of a given standard reflection must match (_cell_modulation_dimension + 3) and the order of the additional indices must be consistent with the codes given in _cell_wave_vector_seq_id. ; ######################## ## EXPTL_CRYSTAL_FACE ## ######################## data_exptl_crystal_face[ms] _name '_exptl_crystal_face_[ms]' _category category_overview _type null _definition ; Data items in the EXPTL_CRYSTAL_FACE category record details of the crystal faces. Data items in this category are extensions of the core CIF dictionary definitions to the indexing of crystal faces by higher-dimensional components. ; data_exptl_crystal_face_index_m_ loop_ _name '_exptl_crystal_face_index_m_1' '_exptl_crystal_face_index_m_2' '_exptl_crystal_face_index_m_3' '_exptl_crystal_face_index_m_4' '_exptl_crystal_face_index_m_5' '_exptl_crystal_face_index_m_6' '_exptl_crystal_face_index_m_7' '_exptl_crystal_face_index_m_8' _category exptl_crystal_face _type numb # _type_construct '( *-?[0-9]+)' _list yes loop_ _list_reference '_exptl_crystal_face_index_h' '_exptl_crystal_face_index_k' '_exptl_crystal_face_index_l' _definition ; Additional Miller indices of the crystal face associated with the value _exptl_crystal_face_perp_dist when the face is indexed using a multidimensional scheme. The total number of indices must match (_cell_modulation_dimension + 3). The order of the indices must be consistent with the codes given in _cell_wave_vector_seq_id. ; ################### ## EXPTL_CRYSTAL ## ################### data_exptl_crystal[ms] _name '_exptl_crystal_[ms]' _category category_overview _type null _definition ; Data items in the EXPTL_CRYSTAL category record details about experimental measurements on the crystal or crystals used, such as shape, size and density. The new data item added to this category specifies whether the structure is crystalline, modulated or composite. ; data_exptl_crystal_type_of_structure _name '_exptl_crystal_type_of_structure' _category exptl_crystal _type char loop_ _enumeration _enumeration_detail cryst 'crystalline structure' mod 'modulated structure' comp 'composite (misfit) structure' _enumeration_default 'cryst' _definition ; The type of structure. This is used to check the consistency of a CIF: the data blocks that are expected and/or certain characteristic parameters depend on whether the material is classified as crystalline (periodic in three dimensions), modulated or composite. ; ################ ## GEOM_ANGLE ## ################ data_geom_angle[ms] _name '_geom_angle_[ms]' _category category_overview _type null _definition ; Data items in the GEOM_ANGLE category record details about the bond angles, as calculated from the ATOM, CELL and SYMMETRY data. These extensions to the core CIF dictionary definitions record the maximum, minimum and average values of angles and extend the symmetry-operation code used in angle listings to the higher-dimensional superspace form. ; data_geom_angle_ loop_ _name '_geom_angle_max' '_geom_angle_min' '_geom_angle_av' _category geom_angle _type numb _type_conditions esd _list yes _list_reference '_geom_angle_atom_site_label_' _units deg _units_detail 'Degrees' _definition ; Maximum, minimum and average angles in degrees bounded by _geom_angle_atom_site_label_1, *_2, and *_3. The site at *_2 is at the apex of the angle. ; data_geom_angle_site_ssg_symmetry_ loop_ _name '_geom_angle_site_ssg_symmetry_1' '_geom_angle_site_ssg_symmetry_2' '_geom_angle_site_ssg_symmetry_3' _category geom_angle _type char # _type_construct # ; [\.([1-\ # ('_space_group_ssg_symops_number')]\ # ([ _]([0-9])\ # {('_cell_reciprocal_basis_vect_number')})?)] # ; _list yes _list_reference '_geom_angle_atom_site_label_' loop_ _example _example_detail . 'no symmetry or translation to site' 4 '4th symmetry operation applied' 7_6455 '7th symmetry position; +a on x, -b on y' _definition ; The symmetry code of each atom site as the symmetry operation number 'n' and the higher-dimensional translation 'm1...mp'. These numbers are combined to form the code 'n m1...mp' or n_m1...mp. The character string n_m1...mp is composed as follows: 'n' refers to the symmetry operation that is applied to the superspace coordinates. It must match a number given in _space_group_symop_ssg_id. 'm1...mp' refer to the translations that are subsequently applied to the symmetry-transformed coordinates to generate the atom used in calculating the angle. These translations (t1,...tp) are related to (m1...mp) by the relations m1=5+t1, ..., mp=5+tp. By adding 5 to the translations, the use of negative numbers is avoided. The number 'p' must agree with (_cell_modulation_dimension + 3). If there are no cell translations, the translation number may be omitted. If no symmetry operations or translations are applicable, then a single full stop '.' is used. ; ############### ## GEOM_BOND ## ############### data_geom_bond[ms] _name '_geom_bond_[ms]' _category category_overview _type null _definition ; Data items in the GEOM_BOND category record details about bonds, as calculated from the ATOM, CELL and SYMMETRY data. These extensions to the core CIF dictionary definitions record the maximum, minimum and average lengths of bonds and extend the symmetry-operation code used in bond listings to the higher-dimensional superspace form. ; data_geom_bond_distance_ loop_ _name '_geom_bond_distance_max' '_geom_bond_distance_min' '_geom_bond_distance_av' _category geom_bond _type numb _type_conditions esd _list yes _list_reference '_geom_bond_atom_site_label_' _enumeration_range 0.0: _units A _units_detail 'Angstroms' _definition ; Maximum, minimum and average values of the intramolecular bond distance in angstroms. ; data_geom_bond_site_ssg_symmetry_ loop_ _name '_geom_bond_site_ssg_symmetry_1' '_geom_bond_site_ssg_symmetry_2' _category geom_bond _type char # _type_construct # ; [\.([1-\ # ('_space_group_ssg_symops_number')]\ # ([ _]([0-9])\ # {('_cell_reciprocal_basis_vect_number')})?)] # ; _list yes _list_reference '_geom_bond_atom_site_label_' loop_ _example _example_detail . 'no symmetry or translation to site' 4 '4th symmetry operation applied' 7_6455 '7th symmetry position; +a on x, -b on y' _definition ; The symmetry code of each atom site as the symmetry operation number 'n' and the higher-dimensional translation 'm1...mp'. These numbers are combined to form the code 'n m1...mp' or n_m1...mp. The character string n_m1...mp is composed as follows: 'n' refers to the symmetry operation that is applied to the superspace coordinates. It must match a number given in _space_group_symop_ssg_id. 'm1...mp' refer to the translations that are subsequently applied to the symmetry-transformed coordinates to generate the atom used in calculating the bond. These translations (t1,...tp) are related to (m1...mp) by the relations m1=5+t1, ..., mp=5+tp. By adding 5 to the translations, the use of negative numbers is avoided. The number 'p' must agree with (_cell_modulation_dimension + 3). If there are no cell translations, the translation number may be omitted. If no symmetry operations or translations are applicable then a single full stop '.' is used. ; ################## ## GEOM_CONTACT ## ################## data_geom_contact[ms] _name '_geom_contact_[ms]' _category category_overview _type null _definition ; Data items in the GEOM_CONTACT category record details about interatomic contacts, as calculated from the ATOM, CELL and SYMMETRY data. These extensions to the core CIF dictionary definitions record the maximum, minimum and average values of contact distances and extend the symmetry-operation code used in contact-distance listings to the higher-dimensional superspace form. ; data_geom_contact_distance_ loop_ _name '_geom_contact_distance_max' '_geom_contact_distance_min' '_geom_contact_distance_av' _category geom_contact _type numb _type_conditions esd _list yes _list_reference '_geom_contact_atom_site_label_' _enumeration_range 0.0: _units A _units_detail 'Angstroms' _definition ; Maximum, minimum and average values of the interatomic contact distance in angstroms. ; data_geom_contact_site_ssg_symmetry_ loop_ _name '_geom_contact_site_ssg_symmetry_1' '_geom_contact_site_ssg_symmetry_2' _category geom_contact _type char # _type_construct # ; [\.([1-\ # ('_space_group_ssg_symops_number')]\ # ([ _]([0-9])\ # {('_cell_reciprocal_basis_vect_number')})?)] # ; _list yes _list_reference '_geom_contact_atom_site_label_' loop_ _example _example_detail . 'no symmetry or translation to site' 4 '4th symmetry operation applied' 7_6455 '7th symmetry position; +a on x, -b on y' _definition ; The symmetry code of each atom site as the symmetry operation number 'n' and the higher-dimensional translation 'm1...mp'. These numbers are combined to form the code 'n m1...mp' or n_m1...mp. The character string n_m1...mp is composed as follows: 'n' refers to the symmetry operation that is applied to the superspace coordinates. It must match a number given in _space_group_symop_ssg_id. 'm1...mp' refer to the translations that are subsequently applied to the symmetry-transformed coordinates to generate the atom used in calculating the contact. These translations (t1,...tp) are related to (m1...mp) by the relations m1=5+t1, ..., mp=5+tp. By adding 5 to the translations, the use of negative numbers is avoided. The number 'p' must agree with (_cell_modulation_dimension + 3). If there are no cell translations, the translation number may be omitted. If no symmetry operations or translations are applicable, then a single full stop '.' is used. ; ################## ## GEOM_TORSION ## ################## data_geom_torsion[ms] _name '_geom_torsion_[ms]' _category category_overview _type null _definition ; Data items in the GEOM_TORSION category record details about torsion angles, as calculated from the ATOM, CELL and SYMMETRY data. These extensions to the core CIF dictionary definitions record the maximum, minimum and average values of torsion angles and extend the symmetry-operation code used in torsion-angle listings to the higher-dimensional superspace form. ; data_geom_torsion_ loop_ _name '_geom_torsion_max' '_geom_torsion_min' '_geom_torsion_av' _category geom_torsion _type numb _type_conditions esd _list yes _list_reference '_geom_torsion_atom_site_label_' _units deg _units_detail 'Degrees' _definition ; Maximum, minimum and average torsion angles in degrees bounded by the four atom sites identified by the _geom_torsion_atom_site_label_ codes. These must match labels specified as _atom_site_label in the atom list. The torsion- angle definition should be that of Klyne and Prelog (1960). Ref: Klyne, W. & Prelog, V. (1960). Experientia, 16, 521-523. ; data_geom_torsion_site_ssg_symmetry_ loop_ _name '_geom_torsion_site_ssg_symmetry_1' '_geom_torsion_site_ssg_symmetry_2' '_geom_torsion_site_ssg_symmetry_3' '_geom_torsion_site_ssg_symmetry_4' _category geom_torsion _type char # _type_construct # ; [\.([1-\ # ('_space_group_ssg_symops_number')]\ # ([ _]([0-9])\ # {('_cell_reciprocal_basis_vect_number')})?)] # ; _list yes _list_reference '_geom_torsion_atom_site_label_' loop_ _example _example_detail . 'no symmetry or translation to site' 4 '4th symmetry operation applied' 7_6455 '7th symmetry position; +a on x, -b on y' _definition ; The symmetry code of each atom site as the symmetry operation number 'n' and the higher-dimensional translation 'm1...mp'. These numbers are combined to form the code 'n m1...mp' or n_m1...mp. The character string n_m1...mp is composed as follows: 'n' refers to the symmetry operation that is applied to the superspace coordinates. It must match a number given in _space_group_symop_ssg_id. 'm1...mp' refer to the translations that are subsequently applied to the symmetry-transformed coordinates to generate the atom used in calculating the angle. These translations (t1,...tp) are related to (m1...mp) by the relations m1=5+t1, ..., mp=5+tp. By adding 5 to the translations, the use of negative numbers is avoided. The number 'p' must agree with (_cell_modulation_dimension + 3). If there are no cell translations, the translation number may be omitted. If no symmetry operations or translations are applicable, then a single full stop '.' is used. ; ############ ## REFINE ## ############ data_refine[ms] _name '_refine_[ms]' _category category_overview _type null _definition ; Data items in the REFINE category record details about the structure refinement parameters. The new items in this category extend those of the core CIF dictionary and are specific to the refinement of modulated structures. ; data_refine_ls_mod_func_description _name '_refine_ls_mod_func_description' _category refine _type char loop_ _example 'Only displacive modulation. Fourier series.' ; Modulation of atom S(1) described by a non-standard linear sawtooth function ; _definition ; Types of modulation present in the structural model and their parameterization. ; data_refine_ls_mod_hydrogen_treatment _name '_refine_ls_mod_hydrogen_treatment' _category refine _type char loop_ _enumeration _enumeration_detail 'refA' 'refined H-atom displacive modulation parameters only' 'refxyzA' 'refined H-atom coordinates and displacive modulation parameters only' 'refP' 'refined H-atom occupational modulation parameters only' 'refUP' 'refined H-atom U and occupational modulation parameters only' 'nomod' 'no modulation of H-atom parameters' _enumeration_default 'nomod' _definition ; Treatment of hydrogen-atom modulation parameters in the refinement. ; data_refine_ls_mod_overall_phason_coeff _name '_refine_ls_mod_overall_phason_coeff' _category refine _type numb _type_conditions esd _enumeration_range 0.0: _enumeration_default 0.0 _definition ; The phason coefficient used to calculate the overall phason correction. ; data_refine_ls_mod_overall_phason_formula _name '_refine_ls_mod_overall_phason_formula' _category refine _type char loop_ _enumeration _enumeration_detail 'Axe' 'Axe, J. D. (1980). Phys. Rev. B, 21, 4181-4190.' 'Ovr' 'Overhauser, A. W. (1971). Phys. Rev. B, 3, 3173-3182.' _definition ; The expression for the overall phason correction, if used. ; ########### ## REFLN ## ########### data_refln[ms] _name '_refln_[ms]' _category category_overview _type null _definition ; Data items in the REFLN category record details about the reflections used to determine the ATOM_SITE data items. The REFLN data items refer to individual reflections and must be included in looped lists. The REFLNS data items specify the parameters that apply to all reflections. The REFLNS data items are not looped. Data items in this category are extensions of the core CIF dictionary definitions to the indexing of reflections used in the refinement by higher-dimensional components. ; data_refln_index_m_ loop_ _name '_refln_index_m_1' '_refln_index_m_2' '_refln_index_m_3' '_refln_index_m_4' '_refln_index_m_5' '_refln_index_m_6' '_refln_index_m_7' '_refln_index_m_8' _category refln _type numb # _type_construct '( *-?[0-9]+)' _list yes loop_ _list_reference '_refln_index_h' '_refln_index_k' '_refln_index_l' _definition ; Additional Miller indices of a particular reflection in the basis described in _cell_reciprocal_basis_description. The total number of indices must match (_cell_modulation_dimension + 3). The order of the additional indices must be consistent with the codes given in _cell_wave_vector_seq_id. ; ############ ## REFLNS ## ############ data_reflns[ms] _name '_reflns_[ms]' _category category_overview _type null _definition ; Data items in the REFLNS category record details about the reflections used to determine the ATOM_SITE data items. The REFLN data items refer to individual reflections and must be included in looped lists. The REFLNS data items specify the parameters that apply to all reflections. The REFLNS data items are not looped. Data items in this category extend the core CIF dictionary definitions providing independent checks on the range of values recorded for each of the additional Miller indices given in the REFLN category. ; data_reflns_limit_index_m_ loop_ _name '_reflns_limit_index_m_1_max' '_reflns_limit_index_m_1_min' '_reflns_limit_index_m_2_max' '_reflns_limit_index_m_2_min' '_reflns_limit_index_m_3_max' '_reflns_limit_index_m_3_min' '_reflns_limit_index_m_4_max' '_reflns_limit_index_m_4_min' '_reflns_limit_index_m_5_max' '_reflns_limit_index_m_5_min' '_reflns_limit_index_m_6_max' '_reflns_limit_index_m_6_min' '_reflns_limit_index_m_7_max' '_reflns_limit_index_m_7_min' '_reflns_limit_index_m_8_max' '_reflns_limit_index_m_8_min' _category reflns _type numb # _type_construct '( *-?[0-9]+)' _definition ; Maximum and minimum values of the additional Miller indices appearing in _refln_index_m_. The number of ranges must match _cell_modulation_dimension. The order of the additional indices must be consistent with the codes given in _cell_wave_vector_seq_id. These need not be the same as the _diffrn_reflns_limit_index_m_. ; ################# ## SPACE_GROUP ## ################# data_space_group_[ms] _name '_space_group_[ms]' _category category_overview _type null _definition ; The SPACE_GROUP category introduced in the symmetry CIF dictionary (cif_sym.dic) is intended to replace the original core SYMMETRY category. For modulated structures, superspace- group descriptions may be included in the same category, but include the _ssg_ flag to indicate their dimensionality of > 3. ; data_space_group_ssg_IT_number _name '_space_group_ssg_IT_number' _category space_group _type numb _enumeration_range 1.1: _definition ; Superspace-group number from International Tables for Crystallography, Vol. C (2004). Valid only for one-dimensional modulated structures. Ref: International Tables for Crystallography (2004). Vol. C, Chapter 9.8. Dordrecht: Kluwer Academic Publishers. ; data_space_group_ssg_name _name '_space_group_ssg_name' _category space_group _type char _example 'Hall's notation W:-P -2xb -2ya:q q' _definition ; Superspace-group symbol conforming to an alternative definition from that given in _space_group_ssg_name_IT and _space_group_ssg_name_WJJ for one-dimensional modulated structures or to the superspace-group name for higher dimensions. When necessary, indicate the origin and the setting. Use a colon ':' as a separator between the different parts of the superspace-group symbol. Within each part, leave a space between each component. Rules for the notation for Hermann-Mauguin and Hall symbols (if present) are given in the symmetry CIF dictionary (cif_sym.dic) and, partially, in _space_group_ssg_name_IT and _space_group_ssg_name_WJJ. For composites described in a single data block, the superspace group describes the symmetry of the whole structure. The symmetry of each subsystem can be derived using the appropriate W matrices. ; data_space_group_ssg_name_IT _name '_space_group_ssg_name_IT' _category space_group _type char _example 'P n m a (0 0 \g) 0 s 0' _definition ; Superspace-group symbol as given in International Tables for Crystallography, Vol. C (2004). Valid only for one-dimensional modulated structures. The symbol is divided into three parts: the Hermann-Mauguin space-group symbol of the reference structure, the modulation wave vector and the phase shift (or internal translation) associated with each component of the space group. Each component of the space-group name is separated by a space. Subscripts should appear without special symbols and bars should be given as negative signs. The components of the modulation wave vector (in parentheses) and the phase shifts are also separated by a space. For composites described in a single data block, the superspace group describes the symmetry of the whole structure. The symmetry of each subsystem can be derived using the appropriate W matrices. Ref: International Tables for Crystallography (2004). Vol. C, Chapter 9.8. Dordrecht: Kluwer Academic Publishers. ; data_space_group_ssg_name_WJJ _name '_space_group_ssg_name_WJJ' _category space_group _type char _example 'P:P c m n:s s -1' _definition ; Superspace-group symbol as given by de Wolff, Janssen & Janner (1981). Valid only for one-dimensional modulated structures. The symbol is divided into three parts separated by colons ':': the superspace lattice symbol, the Hermann-Mauguin space-group symbol of the reference structure and the phase shift (or internal translation) associated with each component of the space group. Each component of the space-group name is separated by a space. Subscripts should appear without special symbols and bars should be given as negative signs. The phase shifts are also separated by a space. For composites described in a single data block, the superspace group describes the symmetry of the whole structure. The symmetry of each subsystem can be derived using the appropriate W matrices. Ref: Wolff, P. M. de, Janssen, T. & Janner, A. (1981). Acta Cryst. A37, 625-636. ; data_space_group_ssg_WJJ_code _name '_space_group_ssg_WJJ_code' _category space_group _type char _example '28a.10.1/2' _definition ; Superspace-group code as given by de Wolff, Janssen & Janner (1981). Valid only for one-dimensional modulated structures. Ref: Wolff, P. M. de, Janssen, T. & Janner, A. (1981). Acta Cryst. A37, 625-636. ; ####################### ## SPACE_GROUP_SYMOP ## ####################### data_space_group_symop_[ms] _name '_space_group_symop_[ms]' _category category_overview _type null loop_ _example _example_detail # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; loop_ _space_group_symop_ssg_id _space_group_symop_ssg_operation_algebraic 1 x1,x2,x3,x4 2 1/2+x1,1/2-x2,1/2-x3,x4 3 1/2-x1,1/2+x2,-x3,1/2-x4 4 -x1,-x2,1/2+x3,1/2-x4 5 -x1,-x2,-x3,-x4 6 1/2-x1,1/2+x2,1/2+x3,-x4 7 1/2+x1,1/2-x2,x3,1/2+x4 8 x1,x2,1/2-x3,1/2+x4 ; ; Example 1 - example corresponding to the one-dimensional incommensurately modulated structure of K~2~SeO~4~. ; # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _definition ; The SPACE_GROUP_SYMOP category introduced in the symmetry CIF dictionary (cif_sym.dic) is intended to replace the original core SYMMETRY_EQUIV category. It contains information about the symmetry operations of the space group. For modulated structures, superspace-group descriptions may be included in the same category, but include the _ssg_ flag to indicate their dimensionality of > 3. ; data_space_group_symop_ssg_id _name '_space_group_symop_ssg_id' _category space_group_symop _type numb # _type_construct [1-('_space_group_ssg_symops_number')] _list yes _definition ; A numeric code identifying each entry in the _space_group_symop_ssg_operation_algebraic list. ; data_space_group_symop_ssg_operation_algebraic _name '_space_group_symop_ssg_operation_algebraic' _category space_group_symop _type char # _type_construct # ; ( *([1-9]/[1-9])?[-\+]?x[1-3])\ # (,([1-9]/[1-9])?[-\+]?x[1-3]){2}\ # (,([1-9]/[1-9])?[-\+]?\ # x[4-('_cell_reciprocal_basis_vect_number')])\ # {('_cell_modulation_dimension')} # ; _list yes _list_reference '_space_group_symop_ssg_id' _example 'x1,-x2,x3,1/2+x4' _definition ; A parsable string giving one of the symmetry operations of the superspace group in algebraic form. These data will generally be repeated in a loop. Use symbols as necessary according to _cell_modulation_dimension. All symmetry operations should be entered, including the identity operation, those for lattice centring and that for a centre of symmetry, if present. The symbolic notation for coordinates is such that the identity operation is expressed as x1,x2,x3,...,xn. _space_group_symop_ssg_operation_algebraic must always be present in a CIF corresponding to a modulated structure. ; # -- end of file --- end of file --- end of file --- end of file ---