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RESTR
CIF
This category is for describing restraints that cannot be described elsewhere.
_restr.special_details
CIF
Text describing any restraint or constraint that cannot be described using any of the the other restraint items. See also _atom_site_restraints.
RESTR_ANGLE
CIF
Items in this category define angles that were restrained in the final refinement. Atom 2 is at the apex of the angle.
_restr_angle.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_angle.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_angle.atom_site_label_3
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_angle.details
CIF
A free-text description of the restraint.
_restr_angle.diff
CIF
The difference between the target and the refined angle.
_restr_angle.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_angle.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_angle.site_symmetry_3
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_angle.target
CIF
The expectation angle defined by the three atoms. This is the target angle for the restrained refinement.
_restr_angle.target_weight_param
CIF
Weighting parameter = sqrt(1/weight). It is the expectation value of the difference between the refined value and the target. If this parameter is set to zero, the angle will be constrained to refine to the target value. If this item is absent, its value will be taken as zero and the distance will be constrained.
RESTR_DISTANCE
CIF
This category describes restraints applied to distances during the final refinement.
_restr_distance.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_distance.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_distance.details
CIF
A free-text description of the restraint.
_restr_distance.diff
CIF
The difference between the target and the refined distance.
_restr_distance.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_distance.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_distance.target
CIF
The expectation distance between the two atoms. This is the target distance for the restrained refinement.
_restr_distance.target_weight_param
CIF
Weighting parameter = sqrt(1/weight). It is the expectation value of the difference between the refined value and the target. If this parameter is set to zero, the distance will be constrained to refine to the target value. If this item is absent, its value will be taken as zero and the distance will be constrained.
RESTR_DISTANCE_MIN
CIF
Items in this category offer power-law and exponential expressions for a function designed to prevent two atoms occupying the same location.
_restr_distance_min.A
CIF
The weight associated with the difference between the refined distance D and the prescribed minimum distance (B or F) is given by the expression
w = A*(B/D)^C^ + E*exp((D-F)/G)
A and E are dimensionless weighting parameters. Either function could be used alone by setting A or E to zero. The default values of A and E are zero.
If A=0, B and C are undefined; if E=0, F and G are undefined.
A hard-sphere contact can be generated by setting E=1, F=prescribed minimum distance and G=0. In this case G (combined with a non-zero E) should be treated as a flag indicating a hard-sphere interaction with a target distance of F so as to avoid division by zero.
_restr_distance_min.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_distance_min.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_distance_min.B
CIF
See _restr_distance_min.A for description.
_restr_distance_min.C
CIF
See _restr_distance_min.A for description.
_restr_distance_min.details
CIF
A text description of the restraint giving details not given elsewhere.
_restr_distance_min.difference
CIF
The difference in angstroms between the refined distance of approach of the two atoms and the target distance B or F:
difference = D - B or D - F
_restr_distance_min.distance
CIF
The refined distance, D, between the two atoms.
_restr_distance_min.E
CIF
See _restr_distance_min.A for description.
_restr_distance_min.F
CIF
See _restr_distance_min.A for description.
_restr_distance_min.G
CIF
See _restr_distance_min.A for description.
_restr_distance_min.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_distance_min.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
RESTR_EQUAL_ANGLE
CIF
Items in this category list the atoms defining the angles that are restrained to be equal in the final refinement. _atom_site_label_2 is at the apex of the angle.
_restr_equal_angle.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_angle.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_angle.atom_site_label_3
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_angle.class_id
CIF
A character string identifying the class of equal angles to which this angle belongs.
_restr_equal_angle.details
CIF
A text description giving details of an angle in a class of angles that are restrained to be equal.
_restr_equal_angle.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_equal_angle.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_equal_angle.site_symmetry_3
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
RESTR_EQUAL_ANGLE_CLASS
CIF
Items in this category give details of the target angles for each class of angles that are restrained to be equal in the final refinement.
_restr_equal_angle_class.average
CIF
The average angle in the class of angles restrained to be the same after refinement.
_restr_equal_angle_class.average_su
CIF
The actual estimated standard deviation of the angles in the
class from their average after refinement.
This number is expected to be similar to the value set for
_restr_equal_angle_class.target_weight_param.
_restr_equal_angle_class.class_id
CIF
A character string that identifies the class of angles whose properties are described.
_restr_equal_angle_class.details
CIF
A text description giving details of the class of angles that are restrained to be equal.
_restr_equal_angle_class.diff_max
CIF
The maximum deviation of an angle in the class from the class average after refinement.
_restr_equal_angle_class.target_weight_param
CIF
The weighting parameter = sqrt(1/weight). The expectation value of the estimated standard deviation of the angles in the class from their average after refinement. This value determines the weight assigned to the restraint. If it is zero the angles are constrained to be equal. The default value is zero.
RESTR_EQUAL_DISTANCE
CIF
Items in this category list the atoms defining the distances that are restrained to be equal in the final refinement.
_restr_equal_distance.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_distance.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_distance.class_id
CIF
A character string identifying the class of equal distances to which this distance belongs.
_restr_equal_distance.details
CIF
A text description giving details of a distance in a class of distances that are restrained to be equal.
_restr_equal_distance.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_equal_distance.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
RESTR_EQUAL_DISTANCE_CLASS
CIF
Items in this category give details of the target distances for each class of distances that are restrained to be equal in the final refinement.
_restr_equal_distance_class.average
CIF
The average distance in the class of distances restrained to be the same after refinement.
_restr_equal_distance_class.average_su
CIF
The actual estimated standard deviation of the distances in the
class from their average after refinement.
This number is expected to be similar to the value set for
_restr_equal_distance_class.target_weight_param.
_restr_equal_distance_class.class_id
CIF
A character string that identifies the class of distances whose properties are described.
_restr_equal_distance_class.details
CIF
A text description giving details of the class of distances that are restrained to be equal.
_restr_equal_distance_class.diff_max
CIF
The maximum deviation of a distance in the class from the class average after refinement.
_restr_equal_distance_class.target_weight_param
CIF
The weighting parameter = sqrt(1/weight). The expectation value of the estimated standard deviation of the distances in the class from their average after refinement. This value determines the weight assigned to the restraint. If it is zero the distances are constrained to be equal. The default value is zero.
RESTR_EQUAL_TORSION
CIF
Items in this category list the atoms defining the torsion angles that are restrained to be equal in the final refinement. The torsion angle is the dihedral angle between the plane defined by atoms 1, 2 and 3, and the plane defined by atoms 2, 3 and 4.
_restr_equal_torsion.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_torsion.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_torsion.atom_site_label_3
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_torsion.atom_site_label_4
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_equal_torsion.class_id
CIF
A character string identifying the class of equal torsion angles to which this torsion angle belongs.
_restr_equal_torsion.details
CIF
A text description giving details of a torsion angle in a class of torsion angles that are restrained to be equal.
_restr_equal_torsion.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_equal_torsion.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_equal_torsion.site_symmetry_3
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_equal_torsion.site_symmetry_4
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
RESTR_EQUAL_TORSION_CLASS
CIF
Items in this category give details of the target torsion angles for each class of torsion angles that are restrained to be equal in the final refinement.
_restr_equal_torsion_class.average
CIF
The average torsion angle in the class of torsion angles restrained to be the same after refinement.
_restr_equal_torsion_class.average_su
CIF
The actual estimated standard deviation of the distances in the
class from their average after refinement.
This number is expected to be similar to the value set for
_restr_equal_torsion_class.target_weight_param.
_restr_equal_torsion_class.class_id
CIF
A character string that identifies the class of torsion angles whose properties are described.
_restr_equal_torsion_class.details
CIF
A text description giving details of the class of torsion angles that are restrained to be equal.
_restr_equal_torsion_class.diff_max
CIF
The maximum deviation of a torsion angle in the class from the class average after refinement.
_restr_equal_torsion_class.target_weight_param
CIF
The weighting parameter = sqrt(1/weight). This is the
expectation value of the estimated standard deviation
(given in _restr_equal_torsion_class.average_su)
of the torsion angles in the class from their
average after refinement.
This value determines the weight assigned to the target.
If it is zero the torsion angles are constrained to be equal.
The default value is zero.
RESTR_PARAMETER
CIF
This restraint, which will normally be used to restrain
the total occupancy of an atom site, can be used to
restrain the value of
SUM(over the specified atoms){ARAMETER*COEFFICIENT\}
where PARAMETER will usually be the value of the
occupancy (but other allowed quantities such as x, y
and z can be specified in the enumeration) and
COEFFICIENT is a user-defined number with a default
value of 1.0. The restraint requires two loops; the
first defines the atoms in each sum (class) and the
second describes the properties of the class.
_restr_parameter.atom_coefficient
CIF
A parameter that scales the quantity being restrained. It can be used to convert a constraint on occupancy to a constraint on ionic charge.
_restr_parameter_atom.site_label
CIF
The atom-site label for an atom in this class.
_restr_parameter.class_id
CIF
The identifier of the class of restraint applied to the atoms.
_restr_parameter.id
CIF
A unique identifier for each parameter.
RESTR_PARAMETER_CLASS
CIF
This restraint, which will normally be used to restrain
the total occupancy of an atom site, can be used to
restrain the value of
SUM(over the specified atoms){ARAMETER*COEFFICIENT\}
where PARAMETER will usually be the value of the occupancy
(but other allowed quantities such as x, y and z can be
specified in the enumeration) and COEFFICIENT is a user-defined
number with a default value of 1.0.
The restraint requires two loops, the first defines the
atoms in each sum (class) and the second describes the
properties of the class.
_restr_parameter_class.class_id
CIF
The class ID of the restraint described in this category.
_restr_parameter_class.details
CIF
A text description of the restraint.
_restr_parameter_class.parameter_type
CIF
A flag that indicates the nature of the restrained value.
_restr_parameter_class.target
CIF
The target value for the sum of values of the appropriate parameter type multiplied by the _*.target_weight_param.
_restr_parameter_class.target_weight_param
CIF
Weighting parameter = sqrt(1/weight). It is the expectation value of the difference between the refined value of the sum(parameter*coefficient) and the _*_target. If this parameter is set to zero, the sum will be constrained to refine to the target value. If this item is absent, its value will be taken as zero and the distance will be constrained.
RESTR_PLANE
CIF
Items in this category define the atoms that make up each class of plane.
_restr_plane.atom_site_label
CIF
An atom-site label of one of the atoms that form the plane.
_restr_plane.class_id
CIF
A character string that identifies the plane to which this atom is constrained.
_restr_plane.details
CIF
A text string giving details not described elsewhere.
_restr_plane.displacement
CIF
The distance between this atom and the best plane through all the atoms.
_restr_plane.id
CIF
A unique identifier for each line in the list.
_restr_plane.site_symmetry
CIF
The site symmetry of the atom that helps to define the plane to which it is restrained.
_restr_plane.target_weight_param
CIF
The weighting parameter = sqrt(1/weight). The expectation value of the distance in angstroms between this atom and the best plane through all the atoms of the class.
RESTR_PLANE_CLASS
CIF
Items in this category describe the properties of the different groups of atoms that are restrained to form a plane.
_restr_plane_class.class_id
CIF
Class identifier for the plane whose properties are described.
_restr_plane_class.details
CIF
Text describing any special features of the restraint.
_restr_plane_class.displacement_avsu
CIF
The average standard uncertainty of atoms in this plane.
_restr_plane_class.displacement_max
CIF
The distance in angstroms from the plane to the atom furthest removed from the plane.
_restr_plane_class.displacement_max_atom_site_label
CIF
The atom-site label of the atom that lies furthest from the plane defined by this class.
_restr_plane_class.displacement_max_site_symmetry
CIF
The site symmetry of the atom lying furthest from the plane to which it is restrained.
RESTR_RIGID_BODY
CIF
Items in this category list the atoms defining one or more bodies that are constrained to be rigid in the final refinement. This is done by listing the atom-site label and symmetry operation for each atom in each rigid body.
Since rigid bodies are only constrained, not restrained, the rigid body is adequately defined by the refined coordinate in the atom_site list. A second category, RESTR_RIGID_BODY_CLASS, permits a description of each rigid body to be given in a *_details item.
_restr_rigid_body.atom_site_label
CIF
The atom-site labels of an atom in a rigid body.
_restr_rigid_body.class_id
CIF
A character string identifying a rigid body.
_restr_rigid_body.details
CIF
A text description giving details of a rigid body in a class of rigid bodies that are constrained to be equal.
_restr_rigid_body.id
CIF
A unique identifier for each atom in the list of atoms in the RESTR_RIGID_BODY category.
_restr_rigid_body.site_symmetry
CIF
The site symmetry of an atom in a rigid body.
RESTR_RIGID_BODY_CLASS
CIF
Items in this category give details of the different rigid
bodies as defined by _restr_rigid_body.class_id
_restr_rigid_body_class.class_id
CIF
A character string that identifies the rigid body.
It must match one of the values of _restr_rigid_body.class_id.
_restr_rigid_body_class.details
CIF
A text description giving details of a rigid body.
RESTR_TORSION
CIF
Items in this category define torsion angles that were restrained in the final refinement. The torsion angle is the dihedral angle between the plane defined by atoms 1, 2 and 3, and the plane defined by atoms 2, 3 and 4.
_restr_torsion.angle_target
CIF
The angle in degrees to which the torsion angle is restrained. The torsion angle is the dihedral angle between the plane defined by atoms 1, 2 and 3, and the plane defined by atoms 2, 3 and 4.
_restr_torsion.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_torsion.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_torsion.atom_site_label_3
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_torsion.atom_site_label_4
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_torsion.details
CIF
A free-text description of the restraint.
_restr_torsion.diff
CIF
The difference between the target and the refined torsion angle.
_restr_torsion.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_torsion.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_torsion.site_symmetry_3
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_torsion.site_symmetry_4
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_torsion.weight_param
CIF
Weighting parameter = sqrt(1/weight). It is the expectation value of the difference between the refined value and the target. If this parameter is set to zero, the angle will be constrained to refine to the target value. If this item is absent, its value will be taken as zero and the angle will be constrained.
RESTR_U_ISO
CIF
This restraint attempts to make an anisotropic atomic displacement isotropic within the range of the weighting parameter. It corresponds to SHELX ISO.
_restr_U_iso.atom_site_label
CIF
Label of the atom whose atomic displacement parameters are restrained.
_restr_U_iso.weight_param
CIF
The expectation value of the difference between the refined and the isotropic equivalent of the anisotropic atomic displacement parameters. The default value of zero indicates a constraint.
RESTR_U_RIGID
CIF
The items in this category restrains the anisotropic displacement parameters of two atoms to be equal within a certain *_target_weight_param along the direction of the vector joining the atoms.
_restr_U_rigid.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_U_rigid.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_U_rigid.details
CIF
Free-text information about the rigid-bond restraint.
_restr_U_rigid.diff
CIF
The difference between the components along the bond direction of the atomic displacement parameters, U, of the two atoms.
_restr_U_rigid.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_U_rigid.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_U_rigid.target_weight_param
CIF
The weighting parameter = sqrt(1/weight). The expectation value of the difference between the components of the atomic displacement parameter, U, along the bond direction of the two atoms that define the bond. This number is used to assign a weight during refinement. A value of zero causes the restraint to become a constraint. This item has a default value of zero.
_restr_U_rigid.U_parallel
CIF
The average value of the components parallel to the bond of the atomic displacement parameters of the two atoms that define the bond.
RESTR_U_SIMILAR
CIF
This category forces the atomic displacement ellipsoids of atom 2 to be equal to that of atom 1 within the range of the weighting parameter. This is the same as SHELX SIMU.
_restr_U_similar.atom_site_label_1
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_U_similar.atom_site_label_2
CIF
Labels of atom sites subtending distance or angle. Atom 2 is the apex for angular restraints.
_restr_U_similar.site_symmetry_1
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_U_similar.site_symmetry_2
CIF
Data item specifying the symmetry operation codes applied to the atom sites involved in a specific geometric configuration.
The symmetry code of each atom site as the symmetry-equivalent position number 'n' and the cell translation number 'pqr'. These numbers are combined to form the code 'n pqr' or n_pqr.
The character string n_pqr is composed as follows:
n refers to the symmetry operation that is applied to the coordinates stored in _atom_site.fract_xyz. It must match a number given in _space_group_symop.id (or one of its aliases, such as _symmetry_equiv_pos_site_id).
p, q and r refer to the translations that are subsequently
applied to the symmetry transformed coordinates to generate
the atom used in calculating the angle. These translations
(x,y,z) are related to (p,q,r) by the relations
p = 5 + x
q = 5 + y
r = 5 + z
_restr_U_similar.weight_param
CIF
The expectation value of the difference between the anisotropic atomic displacement parameters of the two atoms. The default value of zero represents a constraint.
Revision history
Version 3.1 (2016-11-16) Initial CIF2 version created from STAR2 version provided by Syd Hall
(J Hester)
Version 3.1.1 (2021-03-20) Fixed a CIF2 syntax error.
Removed the _description.text data item from
the 'restr_angle.atom_site_label_1', 'restr_angle.atom_site_label_2'
and 'restr_angle.atom_site_label_3' save frames since the same data
item is already provided in the imported 'restr_label' save frame.
(A. Vaitkus)
International Tables for Crystallography
Volume G: Definition and exchange of crystallographic data
Edited by S. R. Hall and B. McMahon
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An essential guide and reference to CIF for programmers, data managers handling crystal-structure information and practising crystallographers.
