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International
Tables for Crystallography Volume G Definition and exchange of crystallographic data Edited by J. R. Hester and B. McMahon © International Union of Crystallography 2026 |
International Tables for Crystallography (2026). Vol. G. Early view chapter
https://doi.org/10.1107/97809553602060001011 Chapter 4.2 Core dictionary (coreCIF) |
Core dictionary version 3.3.0
_space_group_generator.xyz
Name:_space_group_generator.xyz
Definition:
A parsable string giving one of the symmetry generators of the
space group in algebraic form. If W is a matrix representation
of the rotational part of the generator 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
X' = WX + w.
(Note: X is used to represent the bold italic x in International
Tables for Crystallography Volume A, Chapter 1.5.)
When a list of symmetry generators is given, it is assumed
that the complete list of symmetry operations of the space
group (including the identity operation) can be generated
through repeated multiplication of the generators, that is,
(W3, w3) is an operation of the space group if (W2,w2) and
(W1,w1) [where (W1,w1) is applied first] are either operations
or generators and:
W3 = W2 x W1
w3 = W2 x w1 + w2.
Reference: International Tables for Crystallography (2016). Volume A,
Space-group symmetry, edited by M. I. Aroyo, 6th ed.
Chichester: John Wiley & Sons.
Example:| x,1/2-y,1/2+z | c-glide reflection through the plane (x,1/4,z) chosen as one of the generators of the space group. |
Type: Code
Category:
space_group_generator