An infrared and Raman study of the phase transitions in dimethyltin difluoride

Abstract

Dimethyltin difluoride, for which the methyl groups are disordered under ambient conditions, has been investigated at low temperatures, and at high pressures and room temperature, by infrared and Raman spectroscopy. The low-temperature data indicated that the unit cell is non-centrosymmetric below the known phase transition at 70.4 K. A phase transition was detected at close to 40 kbar on compression from changes in the slope of plots of ν vs. p. The vibrational data indicated that the high-pressure phase is different from the phase stable at low temperatures. In particular, the data indicate that the unit cell of the high-pressure phase is centrosymmetric and is related to the ambient phase via a group-subgroup relationship.