No abstract

Phenylammonium hexafluorosilicate, [C 6 H 5 NH 3 ] 2 SiF 6 , crystallizes at room temperature in the orthorhombic system with probable space group Pmmm. Two structural phase transitions were detected at 226 and 280 K by means of differential scanning calorimetry and basic thermodynamic data were determined for these transitions. The internal vibrational modes of [C 6 H 5 NH 3 ] 2 SiF 6 were studied at room temperature and through the phase transitions by using Raman spectroscopy. These studies indicate that the vibrational state of the phenyl cations is weakly changed during these two phase transitions.