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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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_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.
;

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