Ba5Cl4(H2O)8(VPO5)8: a novel three-dimensional framework solid.

The novel hydrothermally synthesized title compound, pentabarium tetrachloride octahydrate octakis(oxovanadium phosphate), Ba(5)Cl(4)(H(2)O)(8)(VPO(5))(8), crystallizes in the orthorhombic space group Cmca with a unit cell containing four formula units. Two Ba(2+) cations, two Cl(-) anions and the O atoms of four water molecules are situated on the (100) mirror plane, while the third independent Ba(2+) cation is on the intersection of the (100) plane and the twofold axis parallel to a. Two phosphate P atoms are on twofold axes, while the remaining independent P atom and both V atoms are in general positions. The structure is characterized by two kinds of layers, namely anionic oxovanadium phosphate (VPO(5)), composed of corner-sharing VO(5) square pyramids and PO(4) tetrahedra, and cationic barium chloride hydrate clusters, Ba(5)Cl(4)(H(2)O)(8), composed of three Ba(2+) cations linked by bridging chloride anions. The layers are connected by Ba-O bonds to generate a three-dimensional structure.