################################################## # # REVISIONS TO CIF_CORE_2.3.DIC # ITEMS SUBJECT TO APPROVAL BY CORE DMG AND COMCIFS # ################################################## # # Accumulated list of tentatively approved items. # # The following new datanames are proposed in this draft of the revisions to # the core CIF dictionary. # # ATOM SITE # _atom_site_fract_ (modify) # _atom_site_refinement_flags (replace with the following) # _atom_site_refinement_flags_posn # _atom_site_refinement_flags_adp # _atom_site_refinement_flags_occupancy # ATOM SITES # _atom_sites_special_details # CELL # _cell_formula_units_Z # _cell_reciprocal_angle_alpha # _cell_reciprocal_angle_beta # _cell_reciprocal_angle_gamma # _cell_reciprocal_length_a # _cell_reciprocal_length_b # _cell_reciprocal_length_c # CHEMICAL # _chemical_melting_point_gt # _chemical_melting_point_lt # _chemical_properties_biological # _chemical_properties_physical # _chemical_temperature_decomposition # _chemical_temperature_decomposition_gt # _chemical_temperature_decomposition_lt # _chemical_temperature_sublimation # _chemical_temperature_sublimation_gt # _chemical_temperature_sublimation_lt # CITATION # _citation_database_id_CSD # DATABASE # _database_code_depnum_ccdc_fiz # _database_code_depnum_ccdc_journal # _database_code_depnum_ccdc_archive # _database_CSD_history # DIFFRN # _diffrn_ambient_pressure_gt # _diffrn_ambient_pressure_lt # _diffrn_ambient_temperature_gt # _diffrn_ambient_temperature_lt # DIFFRN_SOURCE # _diffrn_source_take-off_angle # DIFFRN_STANDARDS # _diffrn_standards_decay_%_lt # DIFFRN_REFLNS # _diffrn_reflns_measured_faction_resolution_full # _diffrn_reflns_measured_faction_resolution_max # _diffrn_reflns_resolution_full # _diffrn_reflns_resolution_max # EXPTL_CRYSTAL # _exptl_crystal_colour_primary # _exptl_crystal_colour_modifier # _exptl_crystal_colour_lustre # _exptl_crystal_density_meas_gt # _exptl_crystal_density_meas_lt # _exptl_crystal_density_meas_temp_gt # _exptl_crystal_density_meas_temp_lt # _exptl_crystal_recrystallization_method # PUBL # _publ_contact_author_id_iucr # PULB_AUTHOR # _publ_author_id_iucr # REFINE # _refine_ls_shift/su_max_lt # _refine_ls_shift/su_mean_lt # SPACE_GROUP (General information on the space group) # _Space_group_crystal_system # _Space_group_id (Parent to various .sg_id's) # _Space_group_IT_number # _Space_group_name_Hall # _Space_group_name_H-M_alt # SPACE_GROUP_SYMOP (Symmetry operations) # _space_group_symop_id (parent to various .symop_id's) # _space_group_symop_operation_xyz # _space_group_symop_sg_id # ################################################## ################################################## # # ATOM SITE # ################################################## data_atom_site_fract_ loop_ _name '_atom_site_fract_x' '_atom_site_fract_y' '_atom_site_fract_z' _category atom_site _type numb _type_conditions esd _related_item '_atom_site_Cartn_' _related_function alternate _list yes _list_reference '_atom_site_label' # _enumeration_default 0.0 _definition ; Atom site coordinates as fractions of the _cell_length_ values. ; # COMMENT: The default should be deleted since it makes no sense. If the # coordinates are defaulted it is, presumably, because they are not known, not # because the atom is at the origin. # STATUS: Preliminary approval 02-09-23 # COMMENT: The proposal is to replace the following item by the subsequent # three items. The # problem with the current definition is that it requires the character field # to be parsed since any of the seven flags may appear in any order. The # replacement items define unique flags for each possibility. #data_atom_site_refinement_flags # _name '_atom_site_refinement_flags' # _category atom_site # _type char # _list yes # _list_reference '_atom_site_label' loop_ _related_item _related_function '_atom_site_refinement_flags_posn' replace '_atom_site_refinement_flags_adp' replace '_atom_site_refinement_flags_occupancy' replace loop_ _enumeration _enumeration_detail . 'no refinement constraints' S 'special position constraint on site' G 'rigid group refinement of site' R 'riding-atom site attached to non-riding atom' D 'distance or angle restraint on site' T 'thermal displacement constraints' U 'Uiso or Uij restraint (rigid bond)' P 'partial occupancy constraint' _definition ; A concatenated series of single-letter codes which indicate the refinement restraints or constraints applied to this site. This item should not be used. It has been replaced by _atom_site_refinement_flags_posn, _*_adp and _occupancy. It is retained in this dictionary only to provide compatibility with legacy CIFs ; # STATUS: Preliminary approval 02-09-23 data_atom_site_refinement_flags_posn _name '_atom_site_refinement_flags_posn' _category atom_site _type char _list yes _list_reference '_atom_site_label' loop_ _enumeration _enumeration_detail . 'no refinement constraints' D 'distance or angle restraint on site' G 'rigid group refinement of site' R 'riding-atom site attached to non-riding atom' S 'special position constraint on site' DG 'combination of the above constraints' DR 'combination of the above constraints' DS 'combination of the above constraints' GR 'combination of the above constraints' GS 'combination of the above constraints' RS 'combination of the above constraints' DGR 'combination of the above constraints' DGS 'combination of the above constraints' DRS 'combination of the above constraints' GRS 'combination of the above constraints' DGRS 'combination of the above constraints' _definition ; A code which indicates the refinement restraints or constraints applied to the positional coordinates of this site. ; # STATUS: Preliminary approval 02-09-23 data_atom_site_refinement_flags_adp _name '_atom_site_refinement_flags_adp' _category atom_site _type char _list yes _list_reference '_atom_site_label' loop_ _enumeration _enumeration_detail . 'no refinement constraints' T 'atomic displacement constraints' U 'Uiso or Uij restraint (rigid bond)' TU 'Both constraints applied' _definition ; A code which indicates the refinement restraints or constraints applied to this atomic displacement parameters of this site. ; # COMMENT: Are these enumeration details clear? What is the difference # between these two flags? Can both apply at the same time? # STATUS: Preliminary approval 02-09-23 data_atom_site_refinement_flags_occupancy _name '_atom_site_refinement_flags_occupancy' _category atom_site _type char _list yes _list_reference '_atom_site_label' loop_ _enumeration _enumeration_detail . 'no refinement constraints' P 'partial occupancy constraint' _definition ; A code which indicates that refinement restraints or constraints were applied to the occupancy of this site. ; # STATUS: Preliminary approval 02-09-23 ################################################## # # ATOM SITES # ################################################## data_atom_sites_special_details _name '_atom_sites_special_details' _category atom_sites _type char _definition ; Additional information about the atomic coordinates not coded elsewhere in the CIF. ; # COMMENT: This could be useful in transcribing comments in databases. # STATUS: Preliminary approval 02-09-23 ################################################## # # CELL category # ################################################## data_cell_formula_units_Z_prime _name '_cell_formula_units_Z_prime' _category cell _type numb _enumeration_range 1: _definition ; The number of the formula units as specified by _chemical_formula_structural, _chemical_formula_moiety or _chemical_formula_sum in the asymmetric unit of the unit cell given in the CELL category and the space group defined in the SYMMETRY or SPACE GROUP category. This item is used to indicate the number of chemically equivalent molecules in the asymmetric unit. ; # COMMENT: Requested by CCDC # STATUS: Preliminary approval 2002-10-14 data_cell_reciprocal_angle_ loop_ _name '_cell_reciprocal_angle_alpha' '_cell_reciprocal_angle_beta' '_cell_reciprocal_angle_gamma' _category cell _type numb _type_conditions esd _enumeration_range 0.0:180.0 _enumeration_default 90.0 _units deg _units_detail 'degrees' _definition ; The angles defining the reciprocal cell. These are related to those in the real cell by: cos(recip-alpha) = (cos(beta)*cos(gamma) - cos(alpha))/(sin(beta)*sin(gamma)) cos(recip-beta) = (cos(gamma)*cos(alpha) - cos(beta))/(sin(gamma)*sin(alpha)) cos(recip-gamma) = (cos(alpha)*cos(beta) - cos(gamma))/(sin(alpha)*sin(beta)) (M.J.Buerger: X-ray Crystallography; New York, John Wiley & Sons Inc; 1942 p.360) ; # COMMENT: Requested by CCDC # STATUS: Preliminary approval 2002-10-14 data_cell_reciprocal_length_ loop_ _name '_cell_recirpocal_length_a' '_cell_reciprocal_length_b' '_cell_reciprocal_length_c' _category cell _type numb _type_conditions esd _enumeration_range 0.0: _units A^-1^ _units_detail 'reciprocal angstroms' _definition ; The reciprocal cell lengths in inverse Angstroms. These are related to the real cell by the following equation: recip-a = b*c*sin(alpha)/V recip-b = c*a*sin(beta)/V recip-c = a*b*sin(gamma)/V where V is the cell volume. (M.J.Buerger: X-ray Crystallography; New York, John Wiley & Sons Inc; 1942 p.360) ; # COMMENT: Requested by CCDC # STATUS: Preliminary approval 2002-10-14 ################################################### # # CHEMICAL category # ################################################### # CHANGE TO AN EXISTING ITEM # # _chemical_melting_point should have added: # # _type_conditions esd # data_chemical_melting_point_ loop_ _name '_chemical_melting_point_gt' '_chemical_melting_point_lt' _category chemical _type numb _related_item '_chemical_melting_point' _related_function alternate _enumeration_range 0.0: _units K _units_detail 'Kelvins' _definition ; A temperature in Kelvins which represents an upper limit (_*_lt) or a lower limit (_*_gt) to the melting point, the temperature at which a crystalline solid changes to a liquid. These items allow a range of temperatures to be given. _chemical_melting_point should always be used in preference to these items whenever possible. ; # COMMENT: These item are introduced to allow for a maximum or minimum # limit, or a range of temperatures to be given. They are primarily designed # to allow comments in exiting databases to be included in a CIF. # STATUS: Preliminary approval 2002-10-14 data__chemical_properties_biological _name '_chemical_properties_biological' _category chemical _type char loop_ _example ; diverse biological activities including use as a laxative and strong antibacterial activity against S. a ureus and weak activity against cyclooxygenase-1 (COX-1) ; ; antibiotic activity against Bacillus subtilis (ATCC 6051) but no significant activity against Candida albicans (ATCC 14053), Aspergillus flavus (NRRL 6541) and Fusarium verticillioides (NRRL 25457) ; ; weakly potent lipoxygenase nonredox inhibitor ; ; no influenza A virus sialidase inhibitory and plaque reduction activities ; ; low toxicity against Drosophila melanogaster ; _definition ; A free description of the biological properties of the material. ; # COMMENT: Suggested by CCDC for comments found in the CSD # STATUS: Preliminary approval 2002-10-14 data_chemical_properties_physical _name '_chemical_properties_physical' _category chemical _type char loop_ _example air-sensitive moisture-sensitive hygroscopic deliquescent oxygen-sensitive photo-sensitive pyrophoric semiconductor 'ferromagnetic at low temperature' 'paramagnetic and thermochromic' _definition ; A free description of the physical properties of the material. ; # COMMENT: Suggested by CCDC for comments found in the CSD # STATUS: Preliminary approval 2002-10-14 data_chemical_temperature_decomposition _name '_chemical_temperature_decomposition' _category chemical _type numb _type_conditions esd _units K _units_detail Kelvin _example 350 _definition ; The temperature in Kelvin at which a solid decomposes. ; # COMMENT: Suggested by CCDC. # STATUS: Preliminary approval 2002-10-14 data_chemical_temperature_decomposition_* loop_ _name '_chemical_temperature_decomposition_gt' '_chemical_temperature_decomposition_lt' _category chemical _type numb _units K _units_detail Kelvin _related_item '_chemical_temperature_decomposition' _related_function alternate _example 350 _definition ; A temperature below which (_*_lt) or above which (_*_gt) the solid is known to decompose, These items allow a range of temperatures to be given. _chemical_temperature_decomposition should always be used in preference to these items whenever possible. ; # COMMENT: Suggested by CCDC. # STATUS: Preliminary approval 2002-10-14 data_chemical_temperature_sublimation _name '_chemical_temperature_sublimation' _category chemical _type numb _type_conditions esd _units K _units_detail Kelvin _example 350 _definition ; The temperature in Kelvin at which a solid sublimes. ; # COMMENT: Suggested by CCDC. # STATUS: Preliminary approval 2002-10-14 data_chemical_temperature_sublimation_* loop_ _name '_chemical_temperature_sublimation_gt' '_chemical_temperature_sublimation_lt' _category chemical _type numb _units K _units_detail Kelvin _related_item '_chemical_temperature_sublimation' _related_function Alternate _example 350 _definition ; A temperature below which (_*_lt) of above which (_*_gt) the solid is known to sublime, These items allow as range of temperatures to be given. _chemical_temperature_sublimation should always be used in preference to these items whenever possible. ; # COMMENT: Suggested by CCDC. # STATUS: Preliminary approval 2002-10-14 ################################################### # # CITATION category # ################################################### # The following item has already been approved but still needs to be # incorporated into the dictionary. data_citation_database_id_CSD _name '_citation_database_id_CSD' _category citation _type char _list yes _list_reference '_citation_id' _example LEKKUH _definition ; Identifier ('refcode') of the database record in the Cambridge Structural Database containing details of the cited structure. ; # COMMENT: Submitted by Brian McMahon # STATUS: Approved 2001-12-03 #################################################### # # DATABASE Category # #################################################### data_database_code_depnum_ccdc_fiz _name '_database_code_depnum_ccdc_fiz' _category database _type char _definition ; Deposition numbers assigned by the Fachinformatsions Zentrum Karlsruhe (FIZ) to files containing structural information archived by the Cambridge Crystallographic Centre (CCDC) ; # COMMENT: For use in the archives of CCDC. Submitted by CCDC # STATUS: Preliminary approval 2002-02-28 data_database_code_depnum_ccdc_journal _name '_database_code_depnum_ccdc_journal' _category database _type char _definition ; Deposition numbers assigned by various journals to files containing structural information archived by the Cambridge Crystallographic Data Centre (CCDC) ; # COMMENT: For use in the archives of CCDC. Submitted by CCDC # STATUS: Preliminary approval 2002-02-28 data_database_code_depnum_ccdc_archive _name '_database_code_depnum_ccdc_archive' _category database _type char _definition ; Deposition numbers assigned by the Cambridge Crystallographic Data Centre (CCDC) to files containing structural information archived by the CCDC. ; # COMMENT: For use in the archives of CCDC. Submitted by CCDC # STATUS: Preliminary approval 2002-02-28 data _database_CSD_history _name '_database_CSD_history' _category database _type char _list yes _list_reference ? _example ? _definition ; A history of changes made by Cambridge Crystallographic Data Centre and incorporated into the Cambridge Structural Database (CSD). ; # COMMENT: Requested by the CCDC # STATUS: Preliminary approval 2002-11-11 ########################################### # # DIFFRN category # ########################################### data_diffrn_ambient_pressure_ loop_ _name '_diffrn_ambient_pressure_gt' '_diffrn_ambient_pressure_lt' _category diffrn _type numb _type_conditions esd _related_item '_diffrn_ambient_pressure' _related_function alternate _enumeration_range 0.0: _units kPa _units_detail 'kilopascals' _definition ; The mean pressure in kilopascals above which (_*_gt) or below which (_*_lt) the intensities were measured. These items allow for a pressure range to be given. _diffrn_ambient_pressure should always be used in preference to these items whenever possible. ; # COMMENT; Provides for a pressure range to be indicated. # STATUS: Preliminary approval 2002-11-11 data_diffrn_ambient_temperature_ loop_ _name '_diffrn_ambient_temperature_gt' '_diffrn_ambient_temperature_lt' _category diffrn _type numb _type_conditions esd _related_item '_diffrn_ambient_temperature' _related_function alternate _enumeration_range 0.0: _units K _units_detail 'kelvins' _definition ; The mean temperature in kelvins above which (_*_gt) or below which (_*_lt) the intensities were measured. These items allow a range of temperatures to be given. _diffrn_ambient_temperature should always be used in preference to these items whenever possible. ; # COMMENT: Provides for a range of temperatures to be specified. # STATUS: Preliminary approval 2002-11-11 ################################################ # # DIFFRN_SOURCE # ################################################ data_diffrn_source_take-off_angle _name '_diffrn_source_take-off_angle' _category diffrn_source _type numb _enumeration_range 0:90 _units degrees _example 1.53 _definition ; The complement of the angle between the normal to the surface of the x-ray tube target and the primary x-ray beam for beams generated by traditional x-ray tubes. ; # COMMENT: Suggested by the powder DMG. # 2003.06.26 Definition modified by BM # 2003-06-26 Definition further modified by Howard Flack # STATUS: Preliminary approval 2002-11-11 ###################################### # # DIFFRN_STANDARDS category # ###################################### data_diffrn_standards_decay_%_lt _name '_diffrn_standards_decay_%_lt' _category diffrn_standards _type numb _related_item '_diffrn_standards_decay_%' _related_function alternate _enumeration_range :100 _definition ; An upper limit on the percentage decrease in the mean intensity of the set of standard reflections measured at the start of the measurement of the diffraction pattern and at the end. This value is used when the decay is too small to be detected. ; # COMMENT: Many experiments show no detectable decay and there is no provision # for this at the moment other than to enter 0.0. # STATUS: Preliminary approval 2002-11-11 ################################################# # # DIFFRN_REFLNS # ################################################# data_diffrn_reflns_measured_fraction_resolution_full _name '_diffrn_reflns_measured_fraction_resolution_full' _category diffrn_reflns _list yes _type numb _enumeration_range 0:1.0 _related_item '_diffrn_measured_fraction_theta_full' _related_function alternate _definition ; Fraction of unique (symmetry-independent) reflections measured out to the resolution given in _diffrn_reflns_resolution_full. This number should be very close to 1.0, since it represents the fraction of reflections measured in the part of the diffraction pattern that is essentially complete. ; # COMMENT: Replacement for _diffrn_measured_fraction_theta_full, moved to a # more appropriate category and defined in terms of resolution rather than # angle which depends on the radiation used. # 2003-06-26 _related_function 'replace' changed to 'alternate' # STATUS: Preliminary approval 2002-11-11 data__diffrn_reflns_measured_fraction_resolution_max _name '_diffrn_reflns_measured_fraction_resolution_max' _category diffrn_reflns _list yes _type numb _enumeration_range 0:1.0 _related_item '_diffrn_measured_fraction_theta_max' _related_function alternate _definition ; Fraction of unique (symmetry-independent) reflections measured out to the resolution given in _diffrn_reflns_resolution_max. ; # COMMENT: Replacement for _diffrn_measured_fraction_theta_max, moved to a # more appropriate category and defined in terms of resolution rather than # angle which depends on the radiation used. # 2003-06-26 _related_function 'replace' changed to 'alternate' # STATUS: Preliminary approval 2002-11-11 data_diffrn_reflns_resolution_full _name '_diffrn_reflns_resolution_full' _category diffrn_reflns _type numb _enumeration_range 0.0: _units A^-1^ _units_detail 'reciprocal angstroms' _related_item '_diffrn_reflns_theta_full' _related_function alternate _definition ; The resolution in reciprocal angstroms at which the measured reflection count is close to complete. The fraction of unique reflections measured out to this resolution is given by _diffrn_reflns_measured_faction_resolution_full ; # COMMENT: Replacement for _diffrn_reflns_theta_full expressed in terms of # resolution rather than an angle that depends on the radiation used. # 2003-06-26 _related_function 'replace' changed to 'alternate' # STATUS: Preliminary approval 2002-11-11 data_diffrn_reflns_resolution_max _name '_diffrn_reflns_resolution_max' _category diffrn_reflns _type numb _enumeration_range 0.0: _units A^-1^ _units_detail 'reciprocal angstroms' _related_item '_diffrn_reflns_theta_max' _related_function alternate _definition ; Maximum resolution of the measured diffraction pattern. ; # COMMENT: Replacement for _diffrn_reflns_theta_max expressed in terms of # resolution rather than an angle that depends on the radiation used. # 2003-06-26 _related_function 'replace' changed to 'alternate' # STATUS: Preliminary approval 2002-11-11 ################################################# # # EXPTL_CRYSTAL # ################################################# # # The following three items replace _exptl_crystal_colour, replacing the free # description allowed there by a more structured colour description based on # the standardized names adopted by the International Center for Diffraction # Data. This scheme allows for three standardized colour descriptors, each # with its own enumeration list. # data_exptl_crystal_colour_primary _name '_exptl_crystal_colour_primary' _category exptl_crystal _type char _list both _list_reference '_exptl_crystal_id' _related_item '_exptl_crystal_colour' _related_function alternate _definition ; The enumeration list of standardized names developed for the International Center for Diffraction Data. The colour of a crystal is given by the combination of _exptl_crystal_colour_modifier with _exptl_crystal_colour_primary, as in 'dark-green', 'bluish-violet', if necessary combined with _exptl_crystal_colour_lustre, as in 'metallic-green'. ; loop_ _enumeration colourless white black gray brown red pink orange yellow green blue violet data_exptl_crystal_colour_modifier _name '_exptl_crystal_colour_modifier' _category exptl_crystal _type char _list both _list_reference '_exptl_crystal_id' _related_item '_exptl_crystal_colour' _related_function alternate _definition ; The enumeration list of standardized names developed for the International Center for Diffraction Data. The colour of a crystal is given by the combination of _exptl_crystal_colour_modifier with _exptl_crystal_colour_primary, as in 'dark-green', 'bluish-violet', if necessary combined with _exptl_crystal_colour_lustre, as in 'metallic-green'. ; loop_ _enumeration light dark whitish blackish grayish brownish reddish pinkish orangish yellowish greenish bluish data_exptl_crystal_colour_lustre _name '_exptl_crystal_colour_lustre' _category exptl_crystal _type char _list both _list_reference '_exptl_crystal_id' _related_item '_exptl_crystal_colour' _related_function alternate _definition ; The enumeration list of standardized names developed for the International Center for Diffraction Data. The colour of a crystal is given by the combination of _exptl_crystal_colour_modifier with _exptl_crystal_colour_primary, as in 'dark-green', 'bluish-violet', if necessary combined with _exptl_crystal_colour_lustre, as in 'metallic-green'. ; loop_ _enumeration metallic dull clear # # STATUS: Preliminary approval 2003-06-17 data_exptl_crystal_density_meas_ loop_ _name '_exptl_crystal_density_meas_gt' '_exptl_crystal_density_meas_lt' _category exptl_crystal _type numb _type_conditions esd _list both _list_reference '_exptl_crystal_id' _enumeration_range 0.0: _units Mg^-3^ _units_detail 'megagrams per cubic metre' _related_item '_exptl_crystal_density' _related_function alternate _definition ; The lower (_*_gt) or upper limit (_*_lt) on the value of the density measured using standard chemical and physical methods. The units are megagrams per cubic metre (grams per cubic centimetre). These items should not be used to report new experimental work where _exptl_crystal_density_meas should be used. They are intended for use in reporting information in existing databases and archives which would be misleading if reported under _exptl_crystal_density_meas. ; loop_ _example _example_detail '_exptl_crystal_density_meas_lt 1.0' 'specimen floats in water' ; _exptl_crystal_density_meas_gt 2.5 _exptl_crystal_density_meas_lt 5.0 ; 'Only the range within which the density lies was given in the original paper' # # STATUS: Preliminary approval 2003-06-16 data_exptl_crystal_density_meas_temp_* loop_ _name '_exptl_crystal_density_meas_temp_gt' '_exptl_crystal_density_meas_temp_lt' _category exptl_crystal _type numb _type_conditions esd _list both _list_reference '_exptl_crystal_id' _enumeration_range 0.0: _units K _units_detail 'Kelvins' _related_item '_exptl_crystal_density_meas_temp' _related_function alternate _definition ; Temperature in kelvins above which (_*_gt) or below which (_*_lt) _exptl_crystal_density_meas was determined. These items should not be used for reporting new work where the correct temperature of measurement should be given. They are intended for use in reporting information stored in databases or archives which would be misleading if reported under _exptl_crystal_density_meas_temp. ; loop_ _example _example_detail '_exptl_crystal_density_meas_temp_lt 300' ; The density was measured as some unspecified temperature below room temperature. ; # COMMENT: The above two items suggested by CCDC. # # STATUS: Preliminary approval 2003-06-16 data_exptl_crystal_recrystallization_method _name '_exptl_crystal_recrystallization_method' _category exptl_crystal _type char _example ? _definition ; Describes the method used to recrystallize the sample. Sufficient details should be given for the procedure to be repeated. The temperature or temperatures should be given as well as details of the solvent, flux or carrier gas with concentrations or pressures and ambient atmosphere. ; # COMMENT: Suggested by CCDC. # Definition elaborated to give details of what should be included. # STATUS: Preliminary approval 2003-06-16 ########################################################## # # PUBL category # ########################################################## data_publ_contact_author_id_iucr _name '_publ_contact_author_id_iucr' _category publ _type char _list yes _example 2985 _definition ; Identifier in the IUCr contact database of the author submitting the manuscript and datablock. This identifier may be available from the World Directory of Crystallographers (http://wdc.iucr.org). ; # COMMENT: Submitted by Brian McMahon This identifier will allow linking to # other publications or files by the contact author. # (Linking based on name alone is inefficient because # individuals change their names or spelling of the names. A complementary # data name is proposed for the authors in the PUBL_AUTHOR category. # STATUS: Preliminary approval 2003-01-07 ######################################################### # # PUBL_AUTHOR category # ######################################################### data_publ_author_id_iucr _name '_publ_author_id_iucr' _category publ_author _type char _list yes _example 2985 _definition ; Identifier in the IUCr contact database of a publication author. This identifier may be available from the World Directory of Crystallographers (http://wdc.iucr.org). ; # COMMENT: Submitted by Brian McMahon. See _publ_contact_author_id_iucr for # further details. # STATUS: Preliminary approval 2003-01-07 ######################################### # # REFINE category # ######################################### data_refine_ls_shift/su_max_lt _name '_refine_ls_shift/su_max_lt' _category refine _type numb _related_item '_refine_ls_shift/su_max' _related_function alternate _enumeration_range 0.0: _definition ; An upper limit for the largest (ratio of the final least-squares parameter shift divided by the final standard uncertainty). This item is used when the largest value of the shift divided by the final standard uncertainty is too small to measure. ; # STATUS: Preliminary approval 2003-01-07 data_refine_ls_shift/su_mean_lt _name '_refine_ls_shift/su_mean_lt' _category refine _type numb _related_item '_refine_ls_shift/su_mean' _related_function alternate _enumeration_range 0.0: _definition ; An upper limit for the average (ratio of the final least-squares parameter shift divided by the final standard uncertainty). This item is used when the average value of the shift divided by the final standard uncertainty is too small to measure. ; # STATUS: Preliminary approval 2003-01-07 ################################################ # # CATEGORY: SPACE_GROUP # ################################################ data_SPACE_GROUP _name space_group _category category_overview _type null _description ; Contains all the data items that refer to the space group as a whole, such as its name, crystal system etc. It may be looped, for example, in a list of space groups and their properties. Only a subset of the space_group category items appear in the core dictionary. The remainder are found in the cif_sym dictionary. Space group types are identified by their International Tables for Crystallography Vol A number or Schoenflies symbol. Specific settings of the space groups can be identified by their Hall symbol, by specifying their symmetry operations. The commonly-used Hermann-Mauguin symbol determines the space group type uniquely but several different Hermann-Mauguin symbols may refer to the same space group type. It contains information on the choice of the basis, but not on the choice of origin. Different formats for the Hermann_Mauguin symbol are found in the cif_sym dictionary. ; _example ; _space_group_id 1 _space_group_name_H-M_alt 'C 2/c' _space_group_IT_number 15 _space_group_name_Hall '-C 2yc' _space_group_crystal_system monoclinic ; # STATUS: Preliminary approval 2003-03-11 data_space_group_crystal_system _name '_space_group_crystal_system' _category space_group _list both _list_mandatory no _list_reference '_space_group_id' _description ; The name of the system of geometric crystal classes of space groups (crystal system) to which the space group belongs. Note that rhombohedral space groups belong to the trigonal system. ; _type char loop_ _enumeration triclinic monoclinic orthorhombic tetragonal trigonal hexagonal cubic # STATUS: Preliminary approval 2003-03-11 # # THE PREVIOUS ITEM REPLACES _symmetry_cell_setting. The definition of the old # item should be modified to make it clear that the old name is discontinued # (the name is crystallographically incorrect and therefore misleading). The # following items should be added to the dictionary entry for # _symmetry_cell_setting: # # _related_item '_space_group_crystal_system' # _related_function replace # # Incidentally I have removed the _related_item and _related_function from the # definition of _space_group_crystal_system because they are incorrect. It is # the _related_item that should 'replace' the item being defined, not the other # way around. # data_space_group_id _name '_space_group_id' _category space_group _list yes _list_mandatory yes _description ; This is an identifier needed if _space_group_* items are looped. ; _type char loop_ _list_link_child '_space_group_symop_sg_id' # STATUS: Preliminary approval 2003-03-11 data_space_group_IT_number _name '_space_group_IT_number' _category space_group _list both _list_mandatory no _list_reference '_space_group_id' _description ; The number as assigned in International Tables for Crystallography Vol A, specifying the proper affine class (i.e. the orientation preserving affine class) of space groups (crystallographic space group type) to which the space group belongs. This number defines the space group type but not the coordinate system in which it is expressed. ; _type numb _enumeration_range 1:230 # # As above _symmetry_Int_Tables_number should have: # # _related_item '_space_group_IT_number' # _related_function replace # # added, and the _related_item and _related_function lines should be removed # from the cif_sym dictionary. # # STATUS: Preliminary approval 2003-03-11 data_space_group_name_Hall _name '_space_group_name_Hall' _category space_group _list both _list_mandatory no _list_reference '_space_group_id' loop_ _example _example_detail 'P 2c -2ac' 'Equivalent to Pca21' '-I 4bd 2ab 3' 'Equivalent to Ia3d' _description ; Space group symbol defined by Hall (Acta Cryst. (1981) A37, 517-525) (See also International Tables for Crystallography Vol.B (1993) 1.4 Appendix B). Each component of the space group name is separated by a space or an underscore. The use of space is strongly recommended. The underscore is only retained because it was used in earlier archived files. It should not be used in new CIFs. _space_group_name_Hall uniquely defines the space group and its reference to a particular coordinate system. ; _type char # # As above '_symmetry_space_group_name_Hall' should have the following items # added: # # _related_item '_space_group_name_Hall' # _related_function replace # # and the _related_item and _related_function items should be removed # from _space_group_name_Hall in the cif_sym dictionary. # # STATUS: Preliminary approval 2003-03-11 data_space_group_name_H-M_alt _name '_space_group_name_H-M_alt' _category space_group _list both _list_mandatory no _list_reference '_space_group_id' _type char loop_ _example _example_detail ; loop_ _space_group_name_H-M_alt 'C m c m' 'C 2/c 2/m 21/m' 'A m a m' ; 'three examples for the space group number 63.' _description ; *_name_H-M_alt allows for any Hermann-Mauguin symbol to be given. The way in which this item is used is determined by the user and in general is not intended to be interpreted by computer. It may, for example, be used to give one of the extended Hermann-Mauguin symbols given in Table 4.3.1 of International Tables for Crystallography Vol A (1995) or a Hermann-Mauguin symbol for a conventional or unconventional setting. Each component of the space group name is separated by a space or underscore. The use of space is strongly recommended. The underscore is only retained because it was used in earlier archived files. It should not be used in new CIFs. Subscripts should appear without special symbols. Bars should be given as negative signs before the numbers to which they apply. The commonly used Hermann-Mauguin symbol determines the space group type uniquely but a given space group type may be described by more than one Hermann-Mauguin symbol. The space group type is best described using the *_IT_number or *_name_Schoenflies. The Hermann-Mauguin symbol may contain information on the choice of basis though not on the choice of origin. To define the setting uniquely use *_name_Hall or list the symmetry operations. ; # # As above '_symmetry_space_group_name_H-M' should have the following items # added: # # _related_item _space_group_name_H-M_alt # _related_function replacement # # and the _related_item and _related_function should be removed from this item # in the cif_sym dictionary. # # STATUS: Preliminary approval 2003-03-11 ########################################################### # # SPACE GROUP SYMOP # ########################################################### data_SPACE_GROUP_SYMOP _category category_overview _type null _description ; Contains information about the symmetry operations of the space group. ; loop_ _example_detail _example ; The symmetry operations for the space group P21/c ; ; loop_ _space_group_symop_id _space_group_symop_operation_xyz 1 x,y,z 2 -x,-y,-z 3 -x,1/2+y,1/2-z 4 x,1/2-y,1/2+z ; # STATUS: Preliminary approval 2003-03-11 data_space_group_symop_id _description ; An arbitrary identifier that uniquely labels each symmetry operation in the list. ; _type char _name '_space_group_symop_id' _category space_group_symop _list yes _list_mandatory yes # # The following should be added to '_symmetry_equiv_pos_site_id' for the reasons # described above: # # _related_item '_space_group_symop_id' # _related_function replace # # and the _related_item and _related_function items should be removed from the # cif_sym dictionary. # # STATUS: Preliminary approval 2003-03-11 data_space_group_symop_operation_xyz _name '_space_group_symop_operation_xyz' _category space_group_symop _list both _list_mandatory no _list_reference '_space_group_symop_id' loop_ _example _examples_detail 'x,1/2-y,1/2+z' 'c glide reflection through the plane (x,1/4,z)' _description ; A parsable string giving one of the symmetry operations of the space group in algebraic form. If W is a matrix representation of the rotational part of the symmetry operation defined by the positions and signs of x, y and z, and w is a column of translations defined by the fractions, an equivalent position X' is generated from a given position X by the equation: X' = WX + w (Note: X is used to represent bold_italics_x in International Tables for Crystallography Vol. A, Section 5) When a list of symmetry operations is given, it is assumed that the list contains all the operations of the space group (including the identity operation) as given by the representatives of the general position in International Tables for Crystallography Vol. A. ; _type char _item_default_value 'x,y,z' # STATUS: Preliminary approval 2003-03-11 data_space_group_symop_sg_id _name '_space_group_symop_sg_id' _category space_group_symop _list both _list_mandatory no _list_reference _space_group_symop_id loop_ _example _example_detail ? ? _description ; This must match a particular value of _space_group_id allowing the symmetry operation to be identified with a particular space group. ; _type numb _list_link_parent '_space_group.id' # COMMENT: The _space_group items above have all been approved by # COMCIFS. The only question we have to decide is which ones are to be included # in the revised dictionary. Some changes have been made in the descriptions # and examples to make them more appropriate for the core dictionary. # # STATUS: Preliminary approval 2003-03-11