New anion-conducting solid solutions in the NaF-MF3-M2O3 (M=Nd, Bi) systems

New fluorite-related solid solutions have been prepared by solid state reac tion of NaE MF3 and M2O3 (M=Nd, Bi). The dependences of cubic lattice param eter and ionic conductivity versus composition are determined. For the NdOF -based solid solution, the hypothesis of anion conductivity has been suppor ted by measurements of ionic transport number by the emf method. The influe nce of the electronic structure of trivalent cations with different electro nic configurations on the composition and electrical properties of these ne w phases is discussed. (C) 2000 Elsevier Science S.A. All rights reserved.