Halogenoantimonates(III) and Halogenobismuthates(III)--A Rich Family of Ferroelectric Crystals

In this paper a variety of architectures of self-assembled halo-coordinated MX 6 octahedra in ferroelectric halogenoantimonates(III) and halogenobismuthates(III) is illustrated. The dielectric properties of a new ferroelectric [4-NH 2 C 5 H 4 NH][SbCl 4 ] are presented. The para-ferroelectric phase transitions mechanism (C2/c → Cc) at T c = 270.5K is discussed. The phase situation in the [4-NH 2 C 5 H 4 NH][MX 4 ] (where M = Sb, Bi and X = Cl, Br) family is compared.