LAUSR

Abstract Ion mobility and conductivity of Rb0.4Bi0.60–xInxF2.2 (x = 0, 0.05, 0.1, 0.15) solid solutions with fluorite structure have been investigated using 19F NMR, X-ray diffraction and impedance spectroscopy methods. Several types of fluoride ions in the solid solution composition were found by analyzing the 19F NMR spectra at 150 K. Attribution of fluoride ions to the specific sublattice was carried out by deconvolution of the spectra. Diffusion of the fluoride ions above 300–350 K was found to be the dominating type of ionic motion in the fluoride sublattice of solid solutions under study. The influence of the size and polarizability of trivalent cations on the nature of ionic mobility in solid solutions in the RbF–BiF3–InF3 ternary system is discussed. Due to the high ionic conductivity of these solid solutions (1.6×10−3 and 7.3×10−4 S/cm at 500 K for x = 0.10 and 0.05), they can be considered as superionic conductors.