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.