CONSTRAINED REFINEMENTS OF STRUCTURE OF TETRAPHOSPHORUS TRISULFIDE BELOW PLASTIC TRANSITION

The crystal structure of P//4S//3 14 K below its plastic crystal phase transition has been refined to find whether the amplitude of libration is anomalously large. Constrained refinements show there is no detectable molecular distortion owing to crystal forces, and that the molecules move as rigid bodies. The amplitudes of libration of the two symmetry independent molecules are very similar; they show a small variation with direction but are not anomalously large. Measurements nearer the transition are suggested.