caa a22 4500 445390174 CHVBK 20180317143044.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1007/s00710-010-0137-3 doi (NATIONALLICENCE)springer-10.1007/s00710-010-0137-3 Plumboselite, Pb3O2(SeO3), a new oxidation-zone mineral from Tsumeb, Namibia [Elektronische Daten] [Anthony Kampf, Stuart Mills, William Pinch] Plumboselite, ideally Pb3O2(SeO3), is a new selenite (IMA2010-028) from the Tsumeb mine, Namibia. It occurs as fibres on clausthalite and is also associated with smithsonite, mimetite and vaterite. Plumboselite occurs in subparallel to divergent clusters of thin, flattened, colourless fibres up to 0.3mm in length, but not exceeding 5μm in width and 2μm in thickness. The fibres are elongated parallel to [001] and flattened on {010}, with {010} the only form observed. The crystals have a dull to adamantine lustre and a white streak. The tenacity is brittle and the Mohs hardness is estimated to be between 2 and 3. Plumboselite crystals are optically biaxial with parallel extinction and are length fast in all orientations. The Gladstone-Dale relationship predicts n av = 2.115. The high indices of refraction and small crystal size prevented the determination of other optical properties. The calculated density is 7.814g/cm3. The empirical formula (based on 5 O atoms) is Pb2.92Ca0.01Se1.03O5. Plumboselite is orthorhombic, space group Cmc21, a = 10.5384(11), b = 10.7452(13), c = 5.7577(7) Å, V = 651.98(12) Å3 and Z = 4. The five strongest lines in the powder X-ray diffraction pattern are [d obs in Å/(I)/hkl]: 3.155/(100)/221; 1.956/(26)/042,402; 2.886/(22)/311,002; 1.713/(21)/223; 2.691/(17)/040. The crystal structure was solved from single-crystal X-ray diffraction data and refined to R 1 = 0.0371 on the basis of 200 unique reflections with F o > 4σF. The structure is based on double [O2Pb3] chains of edge-sharing oxo-centered [OPb4] tetrahedra along c, between which are sited SeO3 triangles. The two independent Pb2+ atoms and the Se4+ atom have sterochemically active lone electron pairs. Springer-Verlag, 2010 Kampf Anthony Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, 90007, Los Angeles, CA, USA aut Mills Stuart Department of Earth and Ocean Sciences, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut Pinch William 19 Stonebridge Lane, 14534, Pittsford, NY, USA aut Mineralogy and Petrology Springer Vienna 101/1-2(2011-01-01), 75-80 0930-0708 101:1-2<75 2011 101 710 https://doi.org/10.1007/s00710-010-0137-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-010-0137-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kampf Anthony Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, 90007, Los Angeles, CA, USA aut NATIONALLICENCE 700 1- Mills Stuart Department of Earth and Ocean Sciences, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut NATIONALLICENCE 700 1- Pinch William 19 Stonebridge Lane, 14534, Pittsford, NY, USA aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer Vienna 101/1-2(2011-01-01), 75-80 0930-0708 101:1-2<75 2011 101 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer