Fast F− ion conductors, with a tysonite-type structure, were made from anion-deficient non-stoichiometric solid solutions of Ln1−yCdyF3−y (Ln = Ce, Nd). Exchange between the fluoride sub-lattices was identified when y ≠ 0. A second exchange mechanism, at lower temperatures, was found for CeF3 and NdF3. The presence of both electrical anomalies in the temperature dependence of LnF3 (Ln = Ce, Nd) was confirmed by Cp variations and X-ray diffraction analyses as a function of temperature.

Ionic Conductivity Properties and 19F NMR Investigation in Ln1−yCdyF3−y (Ln = Ce, Nd) Solid Solutions with Tysonite-Type Structure I - Ionic Conductivity Properties. M.El Omari, J.Sénégas, J.M.Réau: Solid State Ionics, 1998, 107[3-4], 281-91