Synthesis and study of electric transport properties of REE polytungstates M<sub>10</sub>W<sub>22</sub>O<sub>81</sub> (M–La, Nd)

The M10W22O81 (M–La, Nd, Ce) polytungstates of rare earth elements were synthesized by the solid-phase method and their electrical transport and thermal properties were studied. The electrical conductivity was measured by the electrochemical impedance method depending on the temperature and oxygen pressure in the gas phase. A combination of three methods (electrical conductivity versus oxygen pressure, transport numbers by the EMF method and the Tubandt method) established that the studied polytungstates are oxygen-ion conductors.