The mixed-valent titanium phosphate Li2Ti2(PO4)3 dilithium dititanium(III/IV) tris­(orthophosphate)

摘要

The mixed-valent titanium phosphate, Li2Ti2(PO4)3, has been prepared by the reactive halide flux method. The title compound is isostructural with Li2TiM(PO4)3 (M = Fe, Cr) and Li2FeZr(PO4)3 and has the same ³ ∞[Ti2(PO4)3]²⁻ framework as the previously reported Li3- xM ₂(PO₄)₃ phases. The framework is built up from corner-sharing TiO₆ octa­hedra and PO₄ tetra­hedra, one of which has 2 symmetry. The Li⁺ ions are located on one crystallographic position and reside in the vacancies of the framework. They are surrounded by four O atoms in a distorted tetra­hedral coordination. The classical charge-balance of the title compound can be represented as Li⁺ ₂(Ti³⁺/Ti⁴⁺)(PO₄ ³⁻)₃.