Isomorphous substitutions and conductivity in molybdates Nd5−xLnxMo3O16+y (y∼0.5), where Ln = La, Ce, Pr

Abstract Neodymium substitution in rare earth elements (REE) was studied in the systems Nd 5−x Ln x Mo 3 O 16+y , where Ln = La, Ce, Pr with y ∼0.5 by means of X-ray powder diffraction (including the Rietveld algorithm), scanning electron microscopy (SEM) and by measurements of the electrical conductivity. At x values of 0.5, 0.3, and 5.0 the mixtures of REE oxides with MoO 3 transform to single-phase solid solutions with fluorite-related structure and doubled fluorite unit cell parameters as a result of solid state reactions occurring at 1050 °C. In the systems with La and Pr the unit cell parameter of solid solutions increases with x . While in the system with Ce this parameters decrease. Conductivity of ceramic solid electrolytes increases up to 17 times compared with the unmodified Nd 5 Mo 3 O 16+y .