XmlmmCIF equivalent: symmetry_equiv Data items in the SYMMETRY_EQUIV category list the symmetry equivalent positions for the space group. XmlmmCIF equivalent: symmetry_equiv/pos_as_xyz Symmetry equivalent position in the 'xyz' representation. Except for the space group P1, these data are repeated in a loop. The format of the data item is as per International Tables for Crystallography, Vol. A. (1987). All equivalent positions should be entered, including those for lattice centring and a centre of symmetry, if present. XmlmmCIF equivalent: symmetry_equiv/id The value of _symmetry_equiv.id must uniquely identify a record in the SYMMETRY_EQUIV category. Note that this item need not be a number; it can be any unique identifier.