K0.53Mn2.37Fe1.24(PO4)3

During an attempt to crystallize potassium manganese diiron phosphate KMnFe(2)(PO(4))(3) by the flux method, a new phase, potassium dimanganese iron triphosphate, K(0.53)Mn(2.37)Fe(1.24)(PO(4))(3), was isolated. This phase, whose composition was confirmed by ICP analysis, is isotypic with the alluaudite-like phosphates, thus it exhibits the (A2)(A'2)(A1)(A'1)(A''1)(M1)(M2)(2)(PO(4))(3) general formula. The site occupancies led to the following cation distribution: 0.53 K on A'2 (site symmetry 2), 0.31 Mn on A''1, 1.0 Mn on M1 (site symmetry 2) and (0.62 Fe + 0.38 Mn) on M2. The structure is built up from infinite chains of edge-sharing M1O(6) and M2O(6) octa-hedra. These chains run along [10] and are connected by two different PO(4) tetrahedra, one of which exhibits 2 symmetry. The resulting three-dimensional framework delimits large tunnels parallel to [001], which are partially occupied by the K(+) and Mn(2+) cations.