Synthesis and Characterization of Orthovanadates Compounds Li(1-x)NaxCdVO4(x = 0, 0.25).

Abstract Orthovanadates LiCdVO4 and Li0.75Na0.25CdVO4 compounds have been obtained by the conventional solid-state reaction and characterized by X-ray powder diffraction. The crystal structure determination, of both samples, indicates that they are isostructural. The following crystal data were obtained: orthorhombic, Cmcm, Z = 4, (a = 5.924(1) A, b = 8.980 (2) A, c = 6.504(1) A and V = 346.064(1) A3) for LiCdVO4 and (a = 5.899(1) A, b = 9.039(2) A, c = 6.629(1) A and V = 352.878(1) A3) for Li0.75Na0.25CdVO4. Impedance spectroscopy measurements of LiCdVO4 and Li0.75Na0.25CdVO4 were conducted in the frequency and temperature range (209 Hz–1 MHz) and (582 K–709 K), respectively. Besides, the impedance spectra are well fitted to an equivalent circuit consisting of series combination of grains and grains boundaries. It was found that the non-overlapping small polaron tunneling (NSPT) model is suitable to describe the conduction mechanism in these two compounds.