Crystal structure of pseudojohannite, with a revised formula Cu3(OH)2[(UO2)4O4(SO4)2](H2O)12

• Autoři: PLÁŠIL Jakub; FEJFAROVÁ Karla; WALLWORK Kia Sheree; DUŠEK Michal; ŠKODA Radek; SEJKORA Jiří; ČEJKA Jiří; VESELOVSKÝ František; HLOUŠEK Jan; MEISSER Nicolas; BRUGGER Joel
• Rok publikování: 2012
• Druh: Článek v odborném periodiku
• Časopis / Zdroj: American Mineralogist
• Fakulta / Pracoviště MU: Přírodovědecká fakulta
• Doi: http://dx.doi.org/10.2138/am.2012.4127
• Obor: Fyzika pevných látek a magnetismus
• Klíčová slova: Pseudojohannite; zippeite group; uranyl sulfate; X ray diffraction; crystal structure; chemical composition
• Popis: The crystal structure of pseudojohannite from White Canyon, Utah, was solved by charge-flipping from single-crystal X-ray diffraction data and refined to an Robs = 0.0347, based on 2664 observed reflections. Pseudojohannite from White Canyon is triclinic, P-1, with a = 8.6744(4), b = 8.8692(4), c = 10.0090(5) A, alpha = 72.105(4)degrees, beta = 70.544(4)degrees, gamma = 76.035(4)degrees, and V = 682.61(5) A^3, with Z = 1 and chemical formula Cu3(OH)2[(UO2)4O4(SO4)2](H2O)12. The crystal structure of pseudojohannite is built up from sheets of zippeite topology that do not contain any OH groups; these sheets are identical to those found in zippeites containing Mg2+, Co2+, and Zn2+. The two Cu2+ sites in pseudojohannite are [5]- and [6]-coordinated by H2O molecules and OH groups. The crystal structure of the pseudojohannite holotype specimen from Jáchymov was refined using Rietveld refinement of high-resolution powder diffraction data. Results indicate that the crystal structures of pseudojohannite from White Canyon and Jáchymov are identical.

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