New data for metakirchheimerite from Jáchymov (St. Joachimsthal), Czech Republic

Plášil, Jakub; Čejka, Jiří; Sejkora, Jiří; Hloušek, Jan; Goliáš, Viktor

doi:10.3190/jgeosci.057

Cited by 5 publications

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References 15 publications

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“…However, structural data are still missing for few members of the autunite group such as uranocircite, Ba[(UO 2 )(PO 4 )] 2 (H 2 O) 10 (Weisbach, 1877;Locock et al, 2005a), uranospinite, Ca[(UO 2 )(AsO 4 )] 2 (H 2 O) 11 (Weisbach, 1873;Mrose, 1953), and bassetite, Fe 2þ [(UO 2 )(PO 4 )] 2 (H 2 O) 8 (Hallimond, 1915;Vochten et al, 1984). Furthermore, the autunite group can be assumed to be incomplete with some species remaining to discover in nature such as the hypothetical P analogues of metalode `vite, Zn[(UO 2 )(AsO 4 )] 2 (H 2 O) 8 (Agrinier et al, 1972;Pla ´s ˇil et al, 2010), metakirchheimerite, Co[(UO 2 )(AsO 4 )] 2 (H 2 O) 8 (Walenta, 1958;Pla ´s ˇil et al, 2009), and rauchite, Ni[(UO 2 )(AsO 4 )] 2 (H 2 O) 10 (Pekov et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Crystal structure of arsenuranospathite from Rabejac, Lodève, France

Bo¹,

Hatert²,

Baijot³

et al. 2015

ejm

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The crystal structure of the natural aluminium uranyl arsenate hydrate arsenuranospathite, ideally Al[(UO 2 )(AsO 4 )] 2 F(H 2 O) 20 , from the Rabejac deposit, Lode `ve, France, was solved for the first time. Arsenuranospathite is orthorhombic, space group Pnn2, Z ¼ 2, a ¼ 29.9262(7), b ¼ 7.1323(1), c ¼ 7.1864(1) A ˚, and V ¼ 1533.9(1) A ˚3. The crystal structure was refined from single-crystal X-ray diffraction data to R 1 ¼ 0.0373 for 3348 unique observed reflections, and to wR 2 ¼ 0.0768 for all 3833 unique reflections. The mineral is isostructural with its P-analogue uranospathite, Al[(UO 2 )(PO 4 )] 2 F(H 2 O) 20 ; both minerals contain the autunite-type sheet [(UO 2 )((As,P)O 4 )]-constituted by corner-sharing UO 6 square bipyramids and (As,P)O 4 tetrahedra. Aluminium is linked with water molecules to form an Al(H 2 O) 6 octahedron located in the interlayer of the structure. Eight independent and isolated water molecules are also located in the interlayer. A very complex network of H-bonds links the water molecules together, to the Al octahedra and to the uranyl-arsenate sheets. Fluorine was not accurately located by the current structure model and is supposed to replace some of the H 2 O molecules in the Al(H 2 O) 6 octahedron. The crystal-chemical formula, calculated on the basis of (Ascations per formula unit is (Al 1.02 Cu 0.01 )[(U 0.98 O 2 )(As 0.89 P 0.08 Si 0.02 S 0.01 )O 4 ] 2 (F 0.77 OH 0.05 )(H 2 O) 20.18 .

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Section: Introductionmentioning

confidence: 99%

Crystal structure of arsenuranospathite from Rabejac, Lodève, France

Bo¹,

Hatert²,

Baijot³

et al. 2015

ejm

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“…The majority of ore minerals were deposited during Variscan mineralization from mesothermal fluids (Ondruš et al 2003a, b). Primary and supergene mineralization in this district resulted in extraordinarily rich associations; more than 420 mineral species have been described to date (Ondruš et al 1997(Ondruš et al , 2003cPlášil et al 2009bPlášil et al , 2010bPlášil et al , 2011Sejkora et al 2010a-c;Tvrdý and Plášil 2010).…”

Section: Geological Settingmentioning

confidence: 99%

Interesting supergene Pb-rich mineral association from the Rovnost mining field, Jáchymov (St. Joachimsthal), Czech Republic

Sejkora¹,

Plášil²,

Cı́sařová³

et al. 2012

Jour. Geosci.

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Rich supergene mineral association with prevalence of Pb was found in a shallow gallery of the Rovnost mine, the Jáchymov (St. Joachimsthal) ore district, western Bohemia (Czech Republic). Mimetite occurs as colourless transparent flexible fibres up to 1 mm in length and up to 10 μm in diameter. The fibres form greyish white aggregates (up to 1 cm 2 in area) grown on the surface of gangue strongly affected by supergene alteration. The results of the single crystal X-ray diffraction study of mimetite with R 1 = 0.0381 are fully consistent with data reported previously for this mineral phase. According to electron microprobe study, interesting are namely elevated contents of SiO 4 (up to 0.16 apfu). Among the supergene minerals, cerussite, anglesite, wulfenite, philipsbornite-segnitite minerals, pyromorphite and metazeunerite were determined based on powder X-ray diffraction and electron microprobe analyses. The presence of U (~ 4 wt. % UO 3 ) and As (up to 4 wt. % As 2 O 5 ) in wulfenite is particularly noteworthy. Characteristic of the studied mineral association are elevated and omnipresent contents of F -. This mineral assemblage is considered to be a result of a long-term in-situ weathering in near-surface conditions.

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Crystal structure of bassetite and saléeite: new insight into autunite-group minerals

Hatert

Mees

et al. 2016

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The crystal structures of two autunite-group minerals have been solved recently. The crystal structure of bassetite, Fe 2+ [(UO 2 )(PO 4 )] 2 (H 2 O) 10 , from the type locality in Cornwall, United Kingdom (Basset Mines) was solved for the first time. Bassetite is monoclinic, space group P2 1 /n, a = 6.961(1), b = 20.039(2), c = 6.974(1) A ˚and b = 90.46(1) . The crystal structure of sale ´eite, Mg[(UO 2 )(PO 4 )] 2 (H 2 O) 10 , from Shinkolobwe, Democratic Republic of Congo, was also solved. Sale ´eite is monoclinic, space group P2 1 /n, a = 6.951(1), b = 19.942(1), c = 6.967(1) A ˚and b = 90.58(1) . The crystal structure investigation of bassetite (R 1 = 0.0658 for 1879 observed reflections with |F o | ! 4s F ) and sale ´eite (R 1 = 0.0307 for 1990 observed reflections with |F o | ! 4s F ) confirms that both minerals are topologically identical and that bassetite contains ten water molecules per formula unit. Their structure contains autunite-type sheets, [(UO 2 )(PO 4 )] -, consisting of corner-sharing UO 6 square bipyramids and PO 4 tetrahedra. Iron and magnesium are surrounded by water molecules to form Fe(H 2 O) 6 or Mg(H 2 O) 6 octahedra located in interlayer, between the autunite-type sheets. Two isolated independent water molecules are also located in interlayer. Energy-dispersive X-ray spectroscopy analysis confirmed the chemical composition obtained from structure refinement. These new data prompt a re-assessment of minerals of the autunite and meta-autunite groups.

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New data for metakirchheimerite from Jáchymov (St. Joachimsthal), Czech Republic

Cited by 5 publications

References 15 publications

Crystal structure of arsenuranospathite from Rabejac, Lodève, France

Crystal structure of arsenuranospathite from Rabejac, Lodève, France

Interesting supergene Pb-rich mineral association from the Rovnost mining field, Jáchymov (St. Joachimsthal), Czech Republic

Crystal structure of bassetite and saléeite: new insight into autunite-group minerals

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