Sodium-manganese cyclopentaphosphate: Synthesis and crystal structure

The Na2MnP5O15 compound containing a cyclopentaphosphate anion was obtained for the first time by the direct synthesis from the melt of polyphosphoric acids in the presence of Na+ and Mn4+ ions. The parameters of the monoclin ic unit cell are a = 5.176, b = 13.541, and c = 8.771 Angstrom; beta = 103. 61 degrees; sp, gr, P2(1)/m, and Z = 2. The cyclopentaphosphate anions and the manganese atoms in the structure are octahedrally coordinated with oxyg en atoms and are linked into layers. Sodium anions crosslink the neighborin g layers into a three-dimensional framework. (C) 2000 MAIK "Nauka/Interperi odica".