JENSENITE, A CUPRIC TELLURATE FRAMEWORK STRUCTURE WITH TWO COORDINATIONS OF COPPER1

JOEL D. GRICE
Research Division, Canadian Museum of Nature, P.O. Box 3443, Station "D", Ottawa, Ontario K1P 6P4

LEE A. GROAT
Department of Geological Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4

ANDREW C. ROBERTS
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8

Abstract

The crystal structure of jensenite, Cu32+Te6+O6•2H2O, has been determined and refined to indices R = 3.3 and Rw = 2.5%. The structure is monoclinic, P21/n (14), with cell parameters a 9.224(2), b 9.180(1), c 7.600(1) Å, 102.38(1) , V 628.5(2) Å3, with Z = 4. The structure analysis was essential in determining the valence state of Cu2+ and Te6+ and the number of O2- atoms and H2O groups in the formula. The crystal structure of jensenite contains a sheet of fully occupied edge-sharing [CuO6] and [TeO6] octahedra. These (10) sheets are bonded together through [Cu2 8] dimers (where represents either O atoms or H2O groups). The dimers contain two H2O groups, which reinforce the intersheet linkages via H-bonding. The hexagonal closest packed (HCP) layering in jensenite differs from that in other synthetic and natural cupric tellurates in either the sequence of stacking or the composition of the layers.