ON A VANADYL OXOCUPRATE PHOSPHATE CACU(VO )(PO4)(2) CONTAINING CU2+ AT POSITIONS OF VO2+ IONS AND A COPPER RICH PHASE CACU1.13(VO)(0.87)(PO4)(2)

Single crystals of CaCu(VO)(PO4)(2) (1) and CaCu1.13(VO)(0.87)(PO4)(2) (II) have been prepared using solid state reactions in closed and eva cuated quartz tubes. X-ray characterization led to orthorhombic symmet ry, space group D-2h(16)-Pnma, lattice constants a, b, c (I): 9.708(1) , 9.603(1), 6.913(1) Angstrom and (II): 9.700(1), 9.614(1), 6.896(1) A ngstrom, Z = 4. Strongly deformed CaO8 cubes an connected by planar Cu O4 polygons or square VO1+4 pyramids. Short V-O distances are features of VO2+ groups. Two point positions are occupied in a disordered mann er by Cu2+ and VO2+. The replacement of Cu by VO2+ at one position dep ends on the ratio VO2+ : Cu2+ at the neighbouring position, since othe rwise then would be collisions of the apical oxygen atoms of neighbour ing VO1+4 pyramids.