Indium phosphorus chalcogenides are so far known to occur as InPS 4, In4(P2S6) 3 and In4(P2Se6) 3. Indium thiophosphate, InPS4, is tetragonal, space group 14 ($2), with a = 5.623 (1), c = 9.058 (2) A, c/a = 1.611, V = 286.4 (1) A 3, and Z = 2. Its crystal structure was refined from 753 independent X-ray reflexions measured with an automatic four-circle single-crystal diffractometer to R = 0.038. The absolute configuration was obtained by refinement calculations including anomalous-dispersion factors. In4(P2S6) 3 is monoclinic, space group P2Jc (C2Sh), with a = 6.842 (2), b = 10.528 (2), c = 18.266 (5) A, fl = 107.67 (2) °, V = 1253.7 (4) A, 3, and Z = 2. The crystal structure, refined from 2630 independent X-ray reflexions to an R value of 0.063, was found to be a metal-deficient threefold superstructure of the Fe2P2S 6 type formed by the ordering of metal vacancies. Similar relationships hold for In4(P2Se6) 3 with respect to Fe2P2Se 6 but the former builds up a (C2v), sixfold superstructure of the latter. Indium selenohypodiphosphate is orthorhombic, space group Pba2 8with a = 19.197 (9), b = 11.090 (9), c = 20.067 (7) •, V = 4272.2 (8)/~3, and Z = 6. From analogies with the S compound as well as from geometrical and space-group considerations, its crystal structure was established.
