Phase transitions in the ferroelastic [P(CH3)4]SbCl6 crystal

Differential scanning calorimetry, dilatometric, dielectric and linear birefringence measurements have been used to study the ferroelastic [P(CH3)(4)]SbCl6 crystal. It was found that the crystal undergoes two structural phase transitions, at 350 K (second order) and at 405 K (first order). The x-ray temperature studies showed that at 350 K the crystal changes its symmetry from triclinic P (1) over bar to monoclinic C2/m. Ferroelastic domain structure was found in the room temperature phase (below 350 K).