Phase transition, ferroelasticity and ferroelectricity in Li3InF6

The ternary fluoride Li3InF6 exhibits three allotropic forms, alpha, beta and gamma. Single crystals of the alpha and gamma modifications have been obtained by the Bridgman technique. The X-ray diffraction study shows the low-temperature alpha-form to be monoclinic and the high-temperature gamma-form to be orthorhombic. On the basis of optical and dielectric measurements, simultaneous ferroelastic and probably ferroelectric behaviours are assigned to this compound.