Trigonal double molybdates and tungstates: Ferroelastic phase transitions

Abstract

The overview contains basic information about trigonal double molybdates and tungstates MR(XO4)2, representing a crystal family with layered structure. Their structure features networks of corner-linked RO6 octahedra and XO4 Â tetrahedra. Many compounds of this crystal family exhibit ferroelastic phase transitions. Their ferroelastic properties are discussed, with particular emphasis on the peculiarities of the domain structure. An overview of results of studies on ferroelastic phase transitions, obtained with various experimental methods, is provided. Models of trigonal unit cell distortion are presented for monoclinic phases of KSc(MoO4)2 and RbIn(MoO4)2 crystals.