BaMn^II₂Mn^III(PO₄)₃

Abstract

The title compound, barium trimanganese tris­(ortho­phosphate), was synthesized hydro­thermally. Its structure is isotypic with the lead and strontium analogues AMnII\n2MnIII(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 MnII atom 2/m symmetry, the MnIII 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 MnIIIO6 octa­hedra and PO4 tetra­hedra sharing vertices; the other chain has a zigzag arrangement and is built up from two edge-sharing MnIIO6 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 BaII ions are located. The alkaline earth cation is surrounded by eight O atoms in the form of a slightly distorted bicapped trigonal prism.