BaMn(II) 2Mn(III)(PO4)3

Abstract

The title compound, barium trimanganese tris-(ortho-phosphate), was synthesized hydro-thermally. Its structure is isotypic with the lead and strontium analogues AMn(II) 2Mn(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(III)O6 octa-hedra and PO4 tetra-hedra sharing vertices; the other chain has a zigzag arrangement and is built up from two edge-sharing Mn(II)O6 octa-hedra connected to PO4 tetra-hedra by edges and vertices. The two types of chains are linked through PO4 tetra-hedra 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.

Fig. 1.

The main building units of the crystal structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) x, -y + 1, -z; (ii) -x, y - 1/2, -z; (iii) x, y - 1/2, -z; (iv) -x, -y + 1, -z; (v) x, y, z - 1; (vi) -x, -y + 1/2, z - 1; (vii) -x, -y + 1/2, z; (viii) -x + 1/2, y - 1/2, z + 1/2; (ix) x - 1/2, -y + 1/2, -z + 1/2; (x) -x + 1/2, -y + 1/2, -z + 1/2; (xi) x - 1/2, y - 1/2, z + 1/2; (xii) -x, -y, -z + 1; (xiii) -x + 1/2, -y + 1, z + 1/2; (xiv) -x + 1/2, y, -z + 1/2.]

Fig. 2.

Polyhedral representation of BaMn3(PO4)3 with channels running parallel to [010].