Complex Phosphates M0.5 + xM′x Zr2 − x(PO4)3 (M = Cd, Sr, Pb; M′ = Ni, Cu; 0 ≤ x ≤ 2) with an-NZP Type Structure

Abstract

M_0.5 + _xM′_x Zr_{2 − x}(PO₄)₃ phosphates (M = Cd, Sr, Pb; M′ = Ni, Cu; 0 ≤ x ≤ 2) were synthesized by the sol-gel method with followed by heat treatment. The samples were studied by X-ray diffraction, electron microscopy, microprobe analysis, and IR spectroscopy. The formation of limited solid solutions with an NaZr₂(PO₄)₃ (NZP) structure was established in the studied series. Some tendencies in their crystallographic characteristics depending on the chemical composition were elucidated. The crystal structures of Sr_0.9M′_0.4Zr_1.6(PO₄)₃ phosphates (M′ = Ni, Cu; space group \(R\bar{3}\), Z = 6) were refined using X-ray powder diffraction data by the Rietveld method. The effect of the size factor on the formation of phosphate structures was demonstrated.