IMA 2018-100 = uroxite; IMA 2019-030 = metauroxite

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Marco E. Ciriotti
Messaggi: 26570
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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IMA 2018-100 = uroxite; IMA 2019-030 = metauroxite

Messaggio da Marco E. Ciriotti » lun 02 set, 2019 13:43

Prossima pubblicazione.

Referenza:
▪ Kampf, A.R., Plášil, J., Nash, B.P., Němec, I., Marty, J. (2020): Uroxite and metauroxite, the first two uranyl-oxalate minerals. Mineralogical Magazine, 84, (in press).

Abstract:
Uroxite (IMA2018-100), [(UO2)2(C2O4)(OH)2(H2O)2]·H2O, and metauroxite (2019-030), (UO2)2(C2O4)(OH)2(H2O)2, are the first two uranyl-oxalate minerals. Uroxite was found in the Markey mine, Red Canyon, San Juan County, Utah, USA and in the Burro mine, Slick Rock district, San Miguel County, Colorado, USA. Metauroxite was found only in the Burro mine. Both minerals are post-mining secondary phases found in efflorescent crusts on mine walls. Uroxite occurs as light yellow striated blades exhibiting moderate neon-green fluorescence, ca 2 Mohs hardness, good {101} and {010} cleavages, density(calc) = 4.187 g/cm3; optics: biaxial (–), α = 1.602(2), β = 1.660(2), γ = 1.680(2) (white light), 2Vmeas. = 59(1)°, moderate r > v dispersion, orientation Y = b, Z ^ a = 35° in obtuse β, nonpleochroic. Metauroxite occurs as light yellow crude blades and tablets exhibiting weak green-gray fluorescence, ca 2 Mohs hardness, good {001}cleavage, densitycalc = 4.403 g/cm3; approximate optics: α′ = 1.615(5), γ′ = 1.685(5). Electron probe microanalysis provided UO3 79.60, C2O3 10.02, H2O 10.03, total 99.65 wt.% for uroxite and UO3 82.66, C2O3 10.40, H2O 7.81, total 100.87 wt.% for metauroxite; C2O3 and H2O based on the structures. Uroxite is monoclinic, P21/c, a = 5.5698(2), b = 15.2877(6), c = 13.3724(9) Å, β = 94.015(7)°, V = 1135.86(10) Å3 and Z = 4. Metauroxite is triclinic, P–1, a = 5.5635(3), b = 6.1152(4), c = 7.8283(4) Å, α = 85.572(5), β = 89.340(4), γ = 82.468°, V = 263.25(3) Å3 and Z = 1. In the structure of uroxite (R1 = 0.0333 for 2081 I > 2I reflections), UO7 pentagonal bipyramids share corners forming [U4O24] tetramers, which are linked by C2O4 groups to form corrugated sheets. In the structure of metauroxite (R1 = 0.0648 for 1602 I > 2I reflections) UO7 pentagonal bipyramids share edges forming [U2O12] dimers, which are linked by C2O4 groups to form zig-zag chains.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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Marco E. Ciriotti
Messaggi: 26570
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2018-100 = uroxite; IMA 2019-030 = metauroxite

Messaggio da Marco E. Ciriotti » gio 26 mar, 2020 17:23

Pubblicazione effettuata.

Referenza:
▪ Kampf, A.R., Plášil, J., Nash, B.P., Němec, I., Marty, J. (2020): Uroxite and metauroxite, the first two uranyl-oxalate minerals. Mineralogical Magazine, 84, 131-141.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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