Ion mobility and phase transitions in the compounds K0,65Rb0,35SbF4 and (NH4)0,4Rb0,6SbF4 from NMR and DSC data

Abstract

The NMR and DSC methods are used to study ion mobility and phase transitions in crystalline phases of K0,65Rb0,35SbF4 (I) and (NH4)0,4Rb0,6SbF4 (II). Their 19F and 1H NMR spectra are analyzed to trace the patterns of ion motions in the fluoride and ammonium sublattices at temperatures of 150–500 K and determine the types of motions and the corresponding temperature ranges. The phase transition in compound I is found to lead to a modification in which the dominant type of ion motions is the diffusion of fluoride ions. It is suggested that compounds I and II should demonstrate a conductivity of ≈10−4–10−2 S/cm at temperatures above 450 K.