Phase transition in RbCdZrF7: Structure and thermal properties

Bogdanov, Evgeniy, V; Molokeev, Maxim S.; Gorev, Mikhail, V; Kartashev, Andrey, V; Laptash, Natalia M.; et al. Journal Of Fluorine Chemistry.

X-ray, calorimetric and dilatometric studies of RbCdZrF7 revealed the existence of the second order phase transition Cmcm ↔ P21/m at T0 = 200 K. The structure of the initial and distorted phases is ordered. The phase transition is associated with displacements of fluorine atoms, which leads to minor rotations of the CdF7 and ZrF7 pentagonal bipyramids. A small change in entropy, 0.1R, is characteristic of displacive-type transformations. An anomalously high susceptibility of the transition temperature to hydrostatic pressure was found.