Ion mobility, phase transitions, and ion transport in potassium-ammonium hexafluorozirconates

摘要

The mobility of fluoride and ammonium ions (180-480 K) in compounds K2-n(NH4)(n)ZrF6 (0.2 <= n <= 1.70) was investigated by F-19 and H-1 NMR. Correlations have been found between the composition of the cation sublattice, the character of ion motions, and phase transition temperature in these compounds. The high-temperature modifications with n >= 0.85 of the compounds are characterized by translational diffusion of fluoride and ammonium ions and by uniaxial anisotropy of the F-19 magnetic shielding tensor. The electrophysical characteristics of these compounds were studied in the temperature range 300-480 K.