Single-crystal Raman spectra of phosphorus pentachloride

Abstract

Oriented single-crystal Raman polarisation data are reported for phosphorus pentachloride from use of helium–neon laser excitation. The internal modes of the octahedral PCl₆^– anion and tetrahedral PCl₄⁺ cation can be assigned to their symmetry classes according to the group-theoretical predictions for the primitive unit cell. The degenerate species are all found to undergo splitting owing to the low site symmetry of the ions.