The conductivity of solid solutions, K3-xMxZrF7, where x ranged from 0 to 3, was investigated by using complex impedance spectroscopy. Transient nuclear magnetic resonance measurements were carried out on 19F, 1H and 205Tl in order to determine the mobile species. The experimental results led to the conclusion that long-range motion of the monovalent cations, enhanced by rotational/reorientational motion of the (ZrF7)3- complex anions was responsible for the ionic conductivity of the phases. A comparison of the conductivities of Tl, NH4 and K compounds, and of some of their solid solutions, supported the conclusion that the better values which were found for the pure Tl compound were related to the high polarizability of that ion.

V.Gaumet, C.Latouche, D.Avignant, J.Dupuis: Solid State Ionics, 1994, 74[1-2], 29-35