PREPARATION AND CRYSTAL-STRUCTURE OF (NH4)8NI(HPO4)2(PO4)2MO10O30.12H2O

The structure of (NH4)8Ni(HPO4)2(PO4)2Mo10O30 . 12H2O was determined from single-crystal diffractometer data: triclinic, space group P1BAR, with a = 15.541(1), b = 10.196(5), c = 9.630(1) angstrom, alpha = 110.46(1), beta = 97.51(1), gamma = 94.94(1)-degrees and Z = 1. Full matrix least-squares refinements of 367 parameters gave R = 0.028 for 7222 reflections. The Ni2+ ions are on symmetry centers and are octahedrally coordinated by four water molecules and two oxygen atoms from tertiary phosphate groups. The molybdenum atoms are octahedrally coordinated. The octahedra build two rings, each containing five octahedra which share edges or apices with each other or share apices with the phosphate groups. Two phosphate groups (a tertiary and a secondary) cap each ring of molybdenum octahedra. The water molecules and the ammonium ions have from four to seven contacts within the hydrogen-bonding range (2.7-3.1 angstrom) to water molecules, ammonium ions or anion oxygen atoms.