Corundum(gamma)

Formula : Al2O3

Family: 
Oxides
Space group: 
Trigonal - Hexagonal Scalenohedral HM symbol (-3 2/m) Space Group: R 3c
Dana class: 
4.3.1.1
High temperature: 
High temperature mineral, related to metamorphisme and udersaturated magmas.
Geological context: 
Contact and regionally metamorphosed rocks but also in magma with low silica content (alkaline context)

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
101.961 20.420 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp. -1563869 (Ref.: Internal calculation) -1656900 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p. 52.300 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p. 82.77 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p.
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.
102.98 37.76 -27.98 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p.
Reaction properties

Corundum(gamma) + 6H+ ⇌ 2Al+3 + 3H2O

298.15 K, 1 bar log10K: 21.52 ΔH°r:-277390 J·mol-1 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p.
T(°C) 0 25 60 100 150 200 250 300
log10K 25.94 21.52 16.39 11.64 6.83 2.85 -0.62 -3.81
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-949.992248 -0.158416 61869.865125 339.693425 -2605968.782291