Synthesis, crystal structure, and Raman spectra of mixed oxides K2Pb(MoO4)2–x(CrO4)x and K2 – xPb1 + x(MoO4)(CrO4)1 – x(VO4)x, where x = 0–1

Abstract

Specimens of K₂Pb(MoO₄)_2–x(CrO₄)_x and K_2–xPb_{1 + x}(MoO₄)(CrO₄)_1–x(VO₄)_x (x = 0–1) solid solutions, which crystallize in palmierite structural type with space group R3m, were prepared by a citrate method. Position 3a that has octahedral configuration of oxygen atoms in K₂Pb(MoO₄)_2–x (CrO₄)_x is occupied mainly by lead atoms, the share of potassium in this position is not larger 0.056–0.060(2). The introduction of vanadium cations in K₂Pb(MoO₄)_2–x(CrO₄)_x crystal lattice leads to the complete displacement of potassium cations from MO₆ coordination polyhedron and decrease of Pb–O₆ distances from 2.679(5) to 2.665(4) Å. Interactomic distances in (Pb/K)O₆, (K/P)O₁₀, and (Mo/Cr/V)O₄ coordination polyhedra were calculated.