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.