LAUSR

Abstract Ionic mobility and conductivity in the K 0.5– x Pb x Bi 0.5 F 2+ x and Rb 0.5– x Pb x Bi 0.5 F 2+ x ( x =0.05, 0.09) solid solutions with the fluorite structure have been investigated using the methods of 19 F NMR, X-ray diffraction and impedance spectroscopy. Types of ionic motions in the fluoride sublattice of solid solutions have been established and temperature ranges of their realization have been determined (150–450 K). Diffusion of fluoride ions is a dominating type of ionic motions in the fluoride sublattice of solid solutions under study above 350 K. Due to high ionic conductivity, above 10 –3  S/cm at 450 K, these solid solutions can be used as solid electrolytes in various electrochemical devices and systems.