Index

Modulated structures dictionary (msCIF) version 3.2.1

_geom_torsion.site_ssg_symmetry_1

Definition:

   

      The symmetry code of each atom site as the symmetry operation
      number 'n' and the higher-dimensional translation 'm1...mp'.
      These numbers are combined to form the code 'n m1...mp' or
      n_m1...mp. The character string n_m1...mp is composed as follows:
      'n' refers to the symmetry operation that is applied to the
      superspace coordinates. It must match a number given in
      _space_group_symop_ssg_id. 'm1...mp' refer to the translations
      that are subsequently applied to the symmetry-transformed
      coordinates to generate the atom used in calculating the angle.
      These translations (t1,...tp) are related to (m1...mp) by the
      relations m1=5+t1, ..., mp=5+tp. By adding 5 to the
      translations, the use of negative numbers is avoided. The number
      'p' must agree with (_cell_modulation_dimension + 3). If there
      are no cell translations, the translation number may be omitted.
      If no symmetry operations or translations are applicable,
      then a single full stop '.' is used.

Type: Symop

Category:
geom_torsion