New Solid Solution and Phase Equilibria in the Subsolidus Area of the Three-Component CuO-V₂O₅-Ta₂O₅ Oxide System

The results of the study of the three-component system of CuO-V₂O₅-Ta₂O₅ oxides showed, inter alia, that in the air atmosphere in one of its cross-sections, i.e., in the CuV₂O₆-CuTa₂O₆ system, a new substitutional solid solution with the general formula CuTa_2-xV_xO₆ and homogeneity range for x > 0.0 and x ≤ 0.3 is formed. The influence of the degree of incorporation of V⁵⁺ ions into the CuTa₂O₆ crystal lattice in place of Ta⁵⁺ ions on the unit cell volume, thermal stability and IR spectra of the obtained solid solution was determined. Moreover, the value of the band gap energy of the CuTa_2-xV_xO₆ solid solution was estimated in the range of 0.0 < x ≤ 0.3, and on this basis, the new solid solution was classified as a semiconductor. On the basis of the research results, the studied system of CuO-V₂O₅-Ta₂O₅ oxides was also divided into 12 subsidiary subsystems.