The Raman spectrum of tin tetraiodide

The Raman spectrum of tin tetraiodide has been examined. Some crystal field splitting was observed in the asymmetric stretching mode but in no other bands and the number of external modes is considerably less than the number predicted by group theory. This is evidence for the molecular nature of the crystal lattice. The frequencies of the observed external modes are compared with the values predicted from Mössbauer studies.