Wyckoff set

Definition

A Wyckoff set with respect to a space group G is the set of all points X for which the site-symmetry groups are conjugate subgroups of the normalizer N of G in the group of all affine mappings.

Any Wyckoff position of G is transformed onto itself by all elements of G, but not necessarily by the elements of N. Any Wyckoff set of G is instead transformed onto itself also by those elements of N that are contained in G.

See also

Section 8.3.2 of International Tables of Crystallography, Section A