PREPARATION, CHARACTERIZATION AND CRYSTAL-STRUCTURE OF NEODYMIUM CYCLOHEXAPHOSPHATE HEXAHYDRATE - ND2P6O18-CENTER-DOT-6H(2)O

We describe the chemical preparation and crystal structure of neodymiu m cyclohexaphosphate hexahydrate Nd2P6O18.6H(2)O. This compound is mon oclinic, C2, with a = 24.58(2), b = 9.20(1), c = 12.14(2) Angstrom, be ta = 93.97(8)degrees, Z = 4, V = 2739(6) Angstrom(3) and rho(cal.) = 2 .11 g/cm(3). This new type of noncentric atomic arrangement has a typi cal layer organization, built by thick corrugated layers of corner sha ring NdO8 and P6O18 entitles, spreading perpendicular to the (c) over right arrow direction. Structure was solved with a final R = 0.062 for 2358 independent reflections. The thermal behavior has been studied c omparing different analysis : DTA, DTG, IR spectroscopy and X-ray diff raction.