Index

Macromolecular dictionary (mmCIF) version 2.0.09

_space_group_symop.operation_xyz

Name:
'_space_group_symop.operation_xyz'

Definition:

   A parsable string giving one of the symmetry operations of the
   space group in algebraic form.  If W is a matrix representation
   of the rotational part of the symmetry operation defined by the
   positions and signs of x, y and z, and w is a column of
   translations defined by the fractions, an equivalent position
   X' is generated from a given position X by the equation

             X' = WX + w

   (Note: X is used to represent bold_italics_x in International
   Tables for Crystallography Vol. A, 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 explicity all the
   symmetry operations required to generate all the atoms in
   the unit cell defined by the setting used.

Example:

x,1/2-y,1/2+z glide reflection through the plane (x,1/4,z), with glide vector 1/2 c

Type: line

Mandatory item: no

Alias:
_space_group_symop_operation_xyz (cif_core.dic version 2.3)

Related item: _symmetry_equiv.pos_as_xyz (alternate)

Category: space_group_symop