Structure cristalline de type alluaudite KNa5Mn3(MoO4)6

The new phase potassium penta-sodium trimanganese hexa-kis(molybdate), KNa5Mn3Mo6O24, has been synthesized using solid-state methods. The structure is composed of M 2O10 (M = Mn, Na) dimers and MoO4 tetra-hedra (point group symmetry 2) sharing corners and forming layers parallel to (100), which are linked via common corners of another type of MO4 tetra-hedra, forming a three-dimensional structure with two types of large channels along [001] in which two types of Na(+) cations (one with site symmetry 2, one with -1) and K(+) cations (site symmetry 2, half-occupation) are located. Mn(2+) and the third type of Na(+) cations are located at the same site M with occupancies of 0.75 and 0.25, respectively. A comparative structural description is provided between the structure of the title compound and those of the related phases Cu1.35Fe3(PO4)3 and NaAgFeMn2(PO4)3.