A VANADIUM(III) MONOPHOSPHATE BUILT-UP FROM RUTILE CHAINS - CDV2O(PO4)2

Single crystals of a new V(III) monophosphate CdV2O(PO4)2 have been prepared and their structure has been determined by X-ray diffraction. The monophosphate crystallizes in the space group Pnma with a = 14.308(2)angstrom, b = 6.318(1)angstrom, c = 7.248(1)angstrom. The tridimensional framework [V2P2O9]infinity is built up from [VO2]infinity rutile chains and [VPO8]infinity chains of corner-sharing VO6 octahedra and PO4 tetrahedra that form [V2PO7]infinity infinite layers waving along (100). Two successive [V2PO7]infinity layers are connected along a through PO4 tetrahedra. The latter share one edge with the VO6 octahedra of one layer forming VPO8 units, and the two opposite corners with two octahedra belonging to the rutile chain of the next layer. This framework delimits small tunnels running along b that are empty, and intersecting [011] tunnels where the cadmium ions are located with a distorted octahedral coordination. (C) 1994 Academic Press. Inc.