The monoclinic form of trilithium dichromium(III) tris-(orthophosphate)

The monoclinic form of trilithium dichromium(III) tris-(ortho-phosphate), Li3Cr2(PO4)3, was prepared by the reactive halide flux method. The structure of the title compound is composed of a three-dimensional anionic framework with composition ∞ (3)[Cr2(PO4)3](3-) and Li(+) ions situated in the empty channels. The rigid framework built up from CrO6 octa-hedra and PO4 tetra-hedra is the same as that found in other monoclinic Li3 M 2(PO4)3 (M = Fe, Sc, V) phases. The three Li(+) cations of Li3Cr2(PO4)3 are unequally disordered over six crystallographically different sites. The classical charge balance of the title compound can be represented as [Li(+)]3[Cr(3+)]2[P(5+)]3[O(2-)]12. Solid-state UV/Vis spectra indicate that the crystal filed splitting (Δ0) of the Cr(3+) ion is around 2.22 eV.