The mixed-valent titanium phosphate, Li(2)Ti(2)(PO(4))(3), dilithium dititanium(III/IV) tris-(orthophosphate)

The mixed-valent titanium phosphate, Li(2)Ti(2)(PO(4))(3), has been prepared by the reactive halide flux method. The title compound is isostructural with Li(2)TiM(PO(4))(3) (M = Fe, Cr) and Li(2)FeZr(PO(4))(3) and has the same (3) (∞)[Ti(2)(PO(4))(3)](2-) framework as the previously reported Li(3-) (x)M(2)(PO(4))(3) phases. The framework is built up from corner-sharing TiO(6) octa-hedra and PO(4) tetra-hedra, 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 tetra-hedral coordination. The classical charge-balance of the title compound can be represented as Li(+) (2)(Ti(3+)/Ti(4+))(PO(4) (3-))(3).