A MIXED-VALENT VANADIUM MONOPHOSPHATE WITH A CHAIN-LIKE STRUCTURE - BA3V2O3(PO4)(3)

A new mixed-valence vanadium monophosphate with a chain-like structure has been synthesized. It crystallizes in the P2(1)2(1)2(1) space grou p with a = 5.137(1), b = 12.418(1), and c = 20.724(3) Angstrom. The st ructure consists of [V2P3O15](infinity) ribbons running along a, whose cohesion is ensured by Ba2+ cations, Each ribbon is built from two so rts of chains:[VPO7](infinity) chains, which consist of corner-sharing VO5, trigonal bipyramids and PO4 tetrahedra, and [VP2O10](infinity) c hains built of VO6 octahedra and PO4 tetrahedra. The vanadium-centered polyhedra are linked together by corner-sharing, so that V2O10 units are formed, Charge ordering is observed on the vanadium species, with V(IV) in the octahedron and V(V) in the bipyramid. (C) 1998 Academic P ress.