New Solid Solution and Phase Equilibria in the Subsolidus Area of the Three-Component CuO–V(2)O(5)–Ta(2)O(5) Oxide System

The results of the study of the three-component system of CuO–V(2)O(5)–Ta(2)O(5) oxides showed, inter alia, that in the air atmosphere in one of its cross-sections, i.e., in the CuV(2)O(6)–CuTa(2)O(6) system, a new substitutional solid solution with the general formula CuTa(2−x)V(x)O(6) and homogeneity range for x > 0.0 and x ≤ 0.3 is formed. The influence of the degree of incorporation of V(5+) ions into the CuTa(2)O(6) crystal lattice in place of Ta(5+) 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−x)V(x)O(6) 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–V(2)O(5)–Ta(2)O(5) oxides was also divided into 12 subsidiary subsystems.