title: Direct methods: the identification of space-group-specific inconsistent three-phase structure invariants.
abstract: Certain space groups often permit the generation of pairs of triple relationships involving the same three parent reflections in different symmetry forms, giving rise to two equally probable invariant estimates which, because of the space-group symmetry, must disagree by an a priori known phase shift. The 230 space groups have been examined to identify those which permit inconsistent triples, and the complete list which describes the forms of the pair of triples and their phase inconsistency is given.
authors.affiliation: Medical Foundation of Buffalo, Inc., NY 14203.
authors.forename: F
authors.initials: F
authors.lastname: Han
authors.forename: D A
authors.initials: DA
authors.lastname: Langs
mesh_terms: D003461:Crystallography; D008433:Mathematics; D015394:Molecular Structure