NASICON-type Li_2.5K_0.16Na_0.34Cr₂(PO₄)₃

A new NASICON-type chromium(III) phosphate, K_0.16Na_0.34Li_2.5Cr₂(PO₄)₃, lithium sodium potassium dichrom­ate tris­(phosphate), has been prepared by solid-state reaction. It consists of CrO₆ octa­hedra and PO₄ tetra­hedra sharing corners to form a three-dimensional framework. The monovalent cations are located in the M1 (six-coordinate) and M2 (four-coordinate) sites of the framework. The M1 site is occupied by Na⁺ and K⁺ cations with 69 (3) and 31 (3)% occupancy, respectively. The Li⁺ ions, Li1 and Li2, are split over two M2 sites in general positions, with 60 (2) and 40 (2)% occupancy, respectively. Atom Li2 is disordered around a threefold inversion axis.