The crystal structure of magnesiozippeite, Mg[(UO2)(2)O-2(SO4)](H2O)(3.5), from East Saddle Mine, San Juan County, Utah (USA)

• Authors: PLÁŠIL Jakub; FEJFAROVÁ Karla; ŠKODA Radek; DUŠEK Michal; MARTY Joe; ČEJKA Jiří
• Year of publication: 2013
• Type: Article in Periodical
• Magazine / Source: Mineralogy and Petrology
• MU Faculty or unit: Faculty of Science
• Doi: http://dx.doi.org/10.1007/s00710-012-0241-7
• Field: Geology and mineralogy
• Keywords: magnesiozippeite; crystal structure
• Description: The crystal structure of natural magnesiozippeite, Mg[(UO2)(2)O-2(SO4)](H2O)(3.5), from East Saddle mine, San Juan County, U.S.A., has been determined by single-crystal X-ray diffraction analysis and refined to R (obs) = 0.0348. The mineral is monoclinic, crystallizing in the space group C2/m, with unit cell parameters a = 8.7005(5), b = 14.2541(6), c = 8.8433(5), beta = 104.408(5)A degrees, V = 1062.24(9) (3) and Z = 4. The structure consists of the structural sheets of zippeite topology, represented by a structure unit [(UO2)(2)O-2(SO4)](2-), and an interlayer where two Mg2+ I broken vertical bar(6) octahedra are located. The crystal structure of natural magnesiozippeite shows considerable differences to the structure of previously reported synthetic analogue, namely in coordination of Mg2+ in the interlayer.

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