BaMn^II₂Mn^III(PO₄)₃

The title compound, barium trimanganese tris­(ortho­phosphate), was synthesized hydro­thermally. Its structure is isotypic with the lead and strontium analogues AMn^II₂Mn^III(PO₄)₃ (A = Pb, Sr). Except for two O atoms on general positions, all atoms are located on special positions. The Ba and one P atom exhibit mm2 symmetry, the Mn^II atom 2/m symmetry, the Mn^III atom and the other P atom .2. symmetry and two O atoms are located on mirror planes. The crystal structure contains two types of chains running parallel to [010]. One chain is linear and is composed of alternating Mn^IIIO₆ octa­hedra and PO₄ tetra­hedra sharing vertices; the other chain has a zigzag arrangement and is built up from two edge-sharing Mn^IIO₆ octa­hedra connected to PO₄ tetra­hedra by edges and vertices. The two types of chains are linked through PO₄ tetra­hedra into an open three-dimensional framework which contains channels parallel to [100] and [010] in which the Ba^II ions are located. The alkaline earth cation is surrounded by eight O atoms in the form of a slightly distorted bicapped trigonal prism.