Created by: Emanuele Ghedini emanuele.ghedini@unibo.it Jesper Friis jesper.friis@sintef.no
The CATEGORY of data items used to describe the parameters of the crystal unit cell and their measurement.
The CIF_CORE group contains the definitions of data items that are common to all domains of crystallographic studies.
The CIF_CORE dictionary records all the CORE data items defined and used with in the Crystallographic Information Framework (CIF).
The DICTIONARY group encompassing the CORE DIFFRACTION data items defined and used with in the Crystallographic Information Framework (CIF).
The CATEGORY of data items used to describe the diffraction experiment.
The CATEGORY of data items used to specify the experimental work prior to diffraction measurements. These include crystallization crystal measurements and absorption-correction techniques used.
The CATEGORY of data items used to describe symmetry equivalent sites in the crystal unit cell.
The CATEGORY of data items used to describe the angles between the axes in the crystal unit cell.
[{'save':cell_length 'file':templ_attr.cif}]
The gas or liquid environment of the crystal sample, if not air.
Mean hydrostatic pressure at which intensities were measured.
Mean hydrostatic pressure above which intensities were measured. These items allow for a pressure range to be given. _diffrn.ambient_pressure should be used in preference to this item when possible.
Index identifying each entry in the _space_group_symop.operation_xyz list. It is normally the sequence number of the entry in that list, and should be identified with the code 'n' in the geometry symmetry codes of the form 'n_pqr'. The identity operation (i.e. _space_group_symop.operation_xyz set to 'x,y,z') should be set to 1.
_space_group_symop.id = Current_Row(space_group_symop) + 1
A parsable string giving one of the symmetry operations of the space group in algebraic form. If W is a matrix representation of the rotational part of the symmetry operation defined by the positions and signs of x, y and z, and w is a column of translations defined by fractions, an equivalent position X' is generated from a given position X by the equation X' = WX + w (Note: X is used to represent bold_italics_x in International Tables for Crystallography Vol. A, Part 5) When a list of symmetry operations is given, it must contain a complete set of coordinate representatives which generates all the operations of the space group by the addition of all primitive translations of the space group. Such representatives are to be found as the coordinates of the general-equivalent position in International Tables for Crystallography Vol. A (2002), to which it is necessary to add any centring translations shown above the general-equivalent position. That is to say, it is necessary to list explicitly all the symmetry operations required to generate all the atoms in the unit cell defined by the setting used.
glide reflection through the plane (x,1/4,z) with glide vector (1/2)c
data_my_awesome_crystal _cell_length_a 1.00(1) _cell_length_b 2.00(2) _cell_length_c 3.00(3)
loop_ _space_group_symop_id _space_group_symop_operation_xyz 1 x,y,z 2 -x,-y,-z 3 -x,1/2+y,1/2-z 4 x,1/2-y,1/2+z