Synthesis and electrical properties of a new fluorite-like anionic conductor in the Nd2O3–MoO3 system (43–47 mol% Nd2O3)

This work addresses phase relations in the Nd2O3–MoO3 system (25–50 mol% Nd2O3) and properties of a fluorite-like compound existing in this system in the composition range of 43–47 mol% Nd2O3. We describe for the first time the crystal growth of this compound. The composition of the crystals is Nd10Mo6O33 (Nd2O3:MoO3 = 5:6, 45.5 mol% Nd2O3), which falls within the above composition range. Dielectric spectroscopy data for polycrystalline Nd14Mo8O45 (within the homogeneity range of the fluorite-like compound) suggest a phase transition at 650–700 °C. The exact mechanism of the transition remains to be clarified. Nd14Mo8O45 has rather high bulk conductivity, approaching 10− 2 S/cm at 800 °C. The low activation energy and key structural features of the compound in question indicate that it is an anionic conductor.