CIF standard codes for IUCr Journals

absolute configuration codes

The following codes should be used with chemical_absolute_configuration.

rm Absolute configuration established by the structure determination of a compound containing a chiral reference molecule of known absolute configuration
ad Absolute configuration established by anomalous dispersion effects in diffraction measurements on the crystal
rmad Absolute configuration established by the structure determination of a compound containing a chiral reference molecule of known absolute configuration and confirmed by anomalous dispersion effects in diffraction measurements on the crystal
syn Absolute configuration has not been established by anomalous dispersion effects in diffraction measurements on the crystal; the enantiomer has been assigned by reference to an unchanging chiral centre in the synthetic procedure
unk Absolute configuration is unknown, there being no firm chemical evidence for its assignment to hand and it having not been established by anomalous dispersion effects in diffraction measurements on the crystal; an arbitrary choice of enantiomer has been made `inapplicable'

cell-setting codes

The following codes should be used with _symmetry_cell_setting.

triclinic rhombohedral
monoclinic trigonal
orthorhombic hexagonal
tetragonal cubic

colour codes

The following colour codes should be used with _exptl_crystal_colour. The code may be constructed from three attributes appearance, intensity and base colour, in that order, of which only the base-colour string is mandatory. The colour code may be enclosed in quotes (e.g. `light blue'), or the attribute strings may be joined by underscore characters (e.g. metallic_gold). Colour codes constructed from two base colours are also allowed (e.g. red-brown).

Appearance Intensity Base colour
metallic dark black
lustrous light blue
translucent intense bronze
fluorescent pale brown
clear   colourless
    gold
    green
    grey
    orange
    pink
    purple
    red
    silver
    violet
    white
    yellow

absorption-type codes

The following codes should be used with _exptl_absorpt_correction_type. Note that this data item should contain only the type code. A reference to the computer program used to apply the absorption corrections should be given in _exptl_absorpt_process_details.

none No absorption corrections applied (default)
analytical Analytical corrections applied using crystal faces (e.g. Tompa method)
integration
numerical
gaussian 		Numerical integration corrections applied using crystal faces
empirical Corrections using intensity measurements
psi-scan Corrections using ψ-scan measurements
multi-scan Corrections using symmetry-related measurements
refdelf Corrections as part of the refinement model
cylinder Corrections for a cylinder mounted on the φ axis
sphere Corrections for a sphere

structure-factor codes

The following codes should be used with _refine_ls_structure_factor_coef.

F Structure-factor magnitude
Fsqd Structure factor squared
Inet Net intensity

H-atom treatment codes

The following codes should be used with _refine_ls_hydrogen_treatment. Note that this data item should only contain the type code. Any detailed text about the determination and refinement of H-atom parameters should be placed in _publ_section_exptl_refinement.

undef H-atom parameters are not defined
noref No refinement of H-atom parameters
refall H-atom parameters are refined independently
refxyz H-atom coordinate parameters are refined only
refU H-atom displacement parameters are refined only
constr H-atom parameters are constrained to parent site (e.g. riding model)
mixed H atoms treated by a mixture of independent and constrained refinement
hetero H-atom parameters are constrained for H atoms on C atoms and refined independently for H atoms on heteroatoms
heteroxyz H-atom parameters are constrained for H atoms on C atoms and only H-atom coordinate parameters are refined for H atoms on heteroatoms
heteroU H-atom parameters are constrained for H atoms on C atoms and only H-atom displacement parameters are refined for H atoms on heteroatoms
hetero-mixed H-atom parameters are constrained for H atoms on C atoms and some heteroatoms, and H-atom parameters are refined independently for H atoms on remaining heteroatoms
heteroxyz-mixed H-atom parameters are constrained for H atoms on C atoms and some heteroatoms, and only H-atom coordinate parameters are refined for H atoms on remaining heteroatoms
heteroU-mixed H-atom parameters are constrained for H atoms on C atoms and some heteroatoms, and only H-atom displacement parameters are refined for H atoms on remaining heteroatoms

weighting-scheme codes

The following codes should be used with _refine_ls_weighting_scheme. Note that this data item should contain only the type code. The weighting expression should be given in _refine_ls_weighting_details.

sigma Based on measured s.u.'s (default)
calc Calculated weights applied

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