Leydetite, Fe(UO2)(SO4)(2)(H2O)(11), a new uranyl sulfate mineral from Mas d'Alary, Lodeve, France

Logo poskytovatele

Varování

Publikace nespadá pod Fakultu sportovních studií, ale pod Přírodovědeckou fakultu. Oficiální stránka publikace je na webu muni.cz.
Autoři

PLÁŠIL Jakub KASATKIN Anatoly ŠKODA Radek NOVÁK Milan KALLISTOVÁ Anna DUŠEK Michal SKÁLA Roman FEJFAROVÁ Karla ČEJKA Jiří MEISSER Nicolas GOETHALS Herman MACHOVIČ Vladimír LAPČÁK Ladislav

Rok publikování 2013
Druh Článek v odborném periodiku
Časopis / Zdroj Mineralogical Magazine
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
Doi http://dx.doi.org/10.1180/minmag.2013.077.4.03
Obor Geologie a mineralogie
Klíčová slova BOND-VALENCE PARAMETERS; CRYSTAL-STRUCTURE; SPECTROSCOPY; ABSORPTION; URANIUM; LENGTHS
Popis Leydetite, monoclinic Fe(UO2)(SO4)(2)(H2O)(11) (IMA 2012-065), is a new supergene uranyl sulfate from Mas d'Alary, Lodeve, Herault, France. It forms yellow to greenish, tabular, transparent to translucent crystals up to 2 mm in size. Crystals have a vitreous lustre. Leydetite has a perfect cleavage on (001). The streak is yellowish white. Mohs hardness is similar to 2. The mineral does not fluoresce under long- or short-wavelength UV radiation. Leydetite is colourless in transmitted light, non-pleochroic, biaxial, with alpha = 1.513(2), gamma = 1.522(2) (further optical properties could not be measured). The measured chemical composition of leydetite, FeO 9.28, MgO 0.37, Al2O3 0.26, CuO 0.14, UO3 40.19, SO3 21.91, SiO2 0.18, H2O 27.67, total 100 wt.%, leads to the empirical formula (based on 21 0 a.p.f.u.), (Fe0.93Mg0.07Al0.04Cu0.01)(Sigma 1.05)(U1.01O2)(S1.96Si0.02)(Sigma 1.98)O-8(H2O)(11). Leydetite is monoclinic, space group C2/c, with a = 11.3203(3), b = 7.7293(2), c = 21.8145(8) angstrom, beta = 102.402(3)degrees, V = 1864.18(10) angstrom(3), Z = 4, and D-calc = 2.55 g cm(-3). The six strongest reflections in the X-ray powder diffraction pattern are [d(obs) in angstrom (I) (hkl)]: 10.625 (100) (002), 6.277 (1) ((1) over bar 11), 5.321 (66) (004), 3.549 (5) (006), 2.663 (4) (008), 2.131 (2) (0 0 10). The crystal structure has been refined from single-crystal X-ray diffraction data to R-1 = 0.0224 for 5211 observed reflections with [I > 3 sigma(I)]. Leydetite possesses a sheet structure based upon the protasite anion topology. The sheet consists of UO2 bipyramids, which share four of their equatorial vertices with SO4 tetrahedra. Each SO4 tetrahedron, in turn, shares two of its vertices with UO7 bipyramids. The remaining unshared equatorial vertex of the bipyramid is occupied by H2O, which extends hydrogen bonds within the sheet to one of a free vertex of the SO4 tetrahedron. Sheets are stacked perpendicular to the c direction. In the interlayer, Fe2+ ions and H2O groups link to the sheets on either side via a network of hydrogen bonds. Leydetite is isostructural with the synthetic compound Mg(UO2)(SO4)(2)(H2O)(11). The name of the new mineral honours Jean Claude Leydet (born 1961), an amateur mineralogist from Brest (France), who discovered the new mineral.
Související projekty:

Používáte starou verzi internetového prohlížeče. Doporučujeme aktualizovat Váš prohlížeč na nejnovější verzi.

Další info