THE CRYSTAL-STRUCTURE OF KAMPHAUGITE-(Y)

The crystal structure of kamphaugite-(Y) from Hortekollen, Norway, Cay (CO3)2(OH).H2O, P4(1)2(1)2, a = 7.434(1), c = 21.793(3) angstrom, Z = 8, has been refined isotropically to R = 0.067 for 2566 observed refle ctions. The structure is built of corrugated sheets parallel to (001), consisting of CO32- groups and polyhedra of Y in 9-coordination and C a in 8-coordination. The hydrogen bonding scheme is predicted from bon d-valence calculations. A higher water content, corresponding to Ca2Y2 (CO3)4(OH)2.3H2O, was obtained from chemical analysis, but is not conf irmed by the structure investigation. Channels present between the cor rugated sheets are not large enough to accomodate an extra water molec ule in a special position.