Uraninite

Formula : UO2

Family: 
Oxides
Space group: 
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F m3m
Dana class: 
5.1.1.1 (5) Oxides Containing Uranium and Thorium (5.1) with a cation charge of 4+ (AO2) (5.1.1)Dana Group
High temperature: 
High temperature hyrothermal veins.
Geological context: 
Granite and syenite pegmatites. Colloform crusts in high temperature hydrothermal veins.

Dernière mise à jour le 25.01.2021

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
 V°
cm3·mol-1
 ΔGºf
J·mol-1
 ΔHºf
J·mol-1
 Sº
J·mol-1·k-1
 CP
J·mol-1·K-1
270.028 24.620 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. -1031816 (Ref.: 97csho/sas) Shock, E.L., Sassani, D.C., and Betz, H., 1997, Uranium in geologic fluids: Estimates of standard partial molal properties, oxidation potentials, and hydrolysis constants at high temperatures and pressures: Geohim. Cosmo. Acta, v. 61, no. 20, pp. 4245-4266 -1084996 (Ref.: Internal calculation) 76.986 (Ref.: 97csho/sas) Shock, E.L., Sassani, D.C., and Betz, H., 1997, Uranium in geologic fluids: Estimates of standard partial molal properties, oxidation potentials, and hydrolysis constants at high temperatures and pressures: Geohim. Cosmo. Acta, v. 61, no. 20, pp. 4245-4266 63.58 (Ref.: 97csho/sas) Shock, E.L., Sassani, D.C., and Betz, H., 1997, Uranium in geologic fluids: Estimates of standard partial molal properties, oxidation potentials, and hydrolysis constants at high temperatures and pressures: Geohim. Cosmo. Acta, v. 61, no. 20, pp. 4245-4266
CP(T) = a + b·T + ·c·T-2 (T in Kelvin)
a
J·mol-1·K-1
 b * 103
J·mol-1·K-2
 c * 10-5
J·K·mol-1
 Maier Kelley Ref.
62.77 31.74 -7.69 (Ref.: 97csho/sas) Shock, E.L., Sassani, D.C., and Betz, H., 1997, Uranium in geologic fluids: Estimates of standard partial molal properties, oxidation potentials, and hydrolysis constants at high temperatures and pressures: Geohim. Cosmo. Acta, v. 61, no. 20, pp. 4245-4266
Reaction properties

Uraninite + 4H+ ⇌ U+4 + 2H2O

298.15 K, 1 bar log10K: -4.84 ΔH°r:-77857 J·mol-1 (Ref.: Internal calculation)
T(°C) 0 25 60 100 150 200 250 300
log10K -3.57 -4.84 -6.24 -7.48 -8.68 -9.68 -10.59 -11.50
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-569.193484 -0.092993 30455.138975 203.612327 -1234913.193399