2017
Gauthierite, KPb[(UO2)(7)O-5(OH)(7)]center dot 8H(2)O, a new uranyl-oxide hydroxy-hydrate mineral from Shinkolobwe with a novel uranyl-anion sheet-topology
OLDS, Travis, Jakub PLÁŠIL, Antony KAMPF, Radek ŠKODA, Peter BURNS et. al.Základní údaje
Originální název
Gauthierite, KPb[(UO2)(7)O-5(OH)(7)]center dot 8H(2)O, a new uranyl-oxide hydroxy-hydrate mineral from Shinkolobwe with a novel uranyl-anion sheet-topology
Autoři
OLDS, Travis (840 Spojené státy), Jakub PLÁŠIL (203 Česká republika), Antony KAMPF (840 Spojené státy), Radek ŠKODA (203 Česká republika, garant, domácí), Peter BURNS (840 Spojené státy), Jiří ČEJKA (203 Česká republika), Vincent BOURGOIN (250 Francie) a Jean-Claude BOULLIARD (250 Francie)
Vydání
European Journal of Mineralogy, STUTTGART, E SCHWEIZERBARTSCHE VERLAGSBUCHHANDLUNG, 2017, 0935-1221
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10504 Mineralogy
Stát vydavatele
Německo
Utajení
není předmětem státního či obchodního tajemství
Impakt faktor
Impact factor: 1.190
Kód RIV
RIV/00216224:14310/17:00100328
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000396823700011
Klíčová slova anglicky
gauthierite; new mineral; uranyl-oxide hydroxy-hydrate; crystal structure; topology; oxidation zone; Shinkolobwe
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 4. 4. 2018 11:14, Ing. Nicole Zrilić
Anotace
V originále
Gauthierite, KPb[(UO2)(7)O-5(OH)(7)]center dot 8H(2)O, is a new uranyl-oxide hydroxy-hydrate mineral from the Shinkolobwe Mine, Democratic Republic of Congo, Africa. It occurs on a matrix of uraninite-bearing quartz gangue associated with soddyite and a minor metazeunerite-metatorbernite series mineral. It is a product of oxidation-hydration weathering of uraninite. Gauthierite is monoclinic, P2(1)/c, with a = 29.844(2) angstrom, b = 14.5368(8) angstrom, c = 14.0406(7) angstrom, beta = 103.708(6)degrees, V = 5917.8(6) angstrom(3) and Z = 8. Prismatic crystals have pronounced lengthwise striations and reach about 1 mm in length. Gauthierite is yellowish orange with a light orange streak and vitreous lustre. The Mohs hardness is similar to 3 to 4. It is brittle with an uneven fracture and perfect cleavage on {0 1 0}. The calculated density based on the empirical formula is 5.437 g/cm(3). Optically, gauthierite is biaxial (-), with alpha = 1.780(5), beta = 1.815(5), gamma = 1.825(5) (white light), 2V(meas.) = 58(1)degrees; dispersion is extreme (r >>nu). The optical orientation is X = b, Y approximate to a*, Z approximate to c (or X = b, Y<^>a=14 degrees in obtuse beta); it is pleochroic with X very pale yellow, Y and Z orange-yellow; X << Y approximate to Z. Electron microprobe analyses (average of 9) provided: K2O 1.29, PbO 7.17, UO3 82.10, H2O 8.78 (structure), total 99.34 wt.%. The empirical formula (based on 34 O a.p.f.u.) is: K0.67Pb0.78U7O34H23.77. The ideal formula is KPb[(UO2)(7)O-5(OH)(7)](H2O)(8), which requires K2O 1.90, PbO 9.00, UO3 80.74, H2O 8.35, total 100 wt.%. Raman and infrared spectral data confirm the presence of UO22+, OH- and molecular H2O. The eight strongest powder X-ray diffraction lines are [d(obs) in angstrom (hkl) I-rel]: 7.28 (020,400) 49, 3.566 (040, -802, -204) 67, 3.192 (622, -224) 100, 2.541 (-842, -244) 18, 2.043 (406) 14, 2.001 (662, -264, 14.2.0) 23, 1.962 (426, -146) 14, and 1.783 (12.0.4, -10.4.6) 17. The crystal structure of gauthierite (R = 0.0567 for 6997 reflections with [I>3 sigma(I)]) contains uranyl-(hydroxo)-oxide sheets with a novel topology that is similar to that of vandendriesscheite, but with a unique chain sequence UDPDPDUPUP, P-4(UD)(6). Adjacent sheets are linked through K+ and Pb2+ cations (the lone 6s(2) pair on Pb atoms is stereoactive).
Návaznosti
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