Počet záznamů: 1

Běhounekite, U(SO.sub.4./sub.).sub.2./sub.(H.sub.2./sub.O).sub.4./sub., from Jachymov (St Joachimsthal), Czech Republic: the first natural U.sup.4+./sup. sulphate

  1. 1.
    0369630 - FZU-D 2012 RIV GB eng J - Článek v odborném periodiku
    Plášil, J. - Fejfarová, Karla - Novák, M. - Dušek, Michal - Škoda, R. - Hloušek, J. - Čejka, J. - Majzlan, J. - Sejkora, J. - Machovič, Vladimír - Talla, D.
    Běhounekite, U(SO4)2(H2O)4, from Jachymov (St Joachimsthal), Czech Republic: the first natural U4+ sulphate.
    Mineralogical Magazine. Roč. 75, č. 6 (2011), s. 2739-2753 ISSN 0026-461X
    Grant CEP: GA ČR(CZ) GAP204/11/0809
    Výzkumný záměr: CEZ:AV0Z10100521; CEZ:AV0Z30460519
    Klíčová slova: uranium minerals * X-ray diffraction * crystal structure * Jana2006
    Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
    Impakt faktor: 1.321, rok: 2011

    Behounekite, orthorhombic U(SO4)2(H2O)4, is the first natural sulphate of U4+. It was found in the Geschieber vein, Jachymov (St Joachimsthal) ore district, Western Bohemia, Czech Republic, crystallized on the altered surface of arsenic. The crystals have a strong vitreous lustre and a grey to greenish grey streak. They are brittle with an uneven fracture and have very good cleavage along {100}. The Mohs hardness is about 2. The empirical formula of behounekite is (U0.99Y0.33)Σ1.02(SO4)1.97(H2O)4. The simplified formula is U(SO4)2(H2O)4. Behounekite is orthorhombic, space group Pnma; the crystal structure consists of layers built up from [8]-coordinate uranium atoms and sulphate tetrahedra. The eight ligands include four oxygen atoms from the sulphate groups and four oxygen atoms from the H2O molecules. Each uranium coordination polyhedron is connected via sulphate tetrahedra with other uranium polyhedra and through hydrogen bonds to the apices of sulphate tetrahedra.
    Trvalý link: http://hdl.handle.net/11104/0203650