Data type: numb
Must appear in a looped list containing '_symmetry_equiv_pos_as_xyz'
Related item: '_space_group_symop_id'
Related function: replace
A code identifying each entry in the _symmetry_equiv_pos_as_xyz list. It is normally the sequence number of the entry in that list, and should be identified with the code 'n' in _geom_*_symmetry_ codes of the form 'n_klm'.