Gibbsite(mc)

Formula : Al(OH)3

Family: 
Hydroxides
Space group: 
Monoclinic - Prismatic HM symbol (2/m) Space Group: P 21/n
Dana class: 
6.3.1.1VI - 6 Hydroxides and Oxides Containing Hydroxyl ; 6.3 Hydroxides and Oxides Containing Hydroxyl with (OH)3 or (OH)6 groups ; 6.2.2
High temperature: 
Stable at room temperature.
Geological context: 
Mineral common in lateritic soils developed on aluminous rocks in areas of high rainfall, but also common in aluminum-bearing byproducts from thermic processes.

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
78.004 31.956 (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. -1145691 (Ref.: 90nor/plu) Nordstrom D.K., Plummer L.N., Langmuir D., Busenberg E., May H.M., Jones B.F., and Parkhurst D.L., 1990. Revised chemical equilibrium data for major water-mineral reactions and their limitations, in Bassett, R.L. and Melchior, D. eds., Chemical modeling in aqueous systems II: Washington D.C., American Chemical Society Symposium Series 416, p. 398-413. -1293380 (Ref.: 90nor/plu) Nordstrom D.K., Plummer L.N., Langmuir D., Busenberg E., May H.M., Jones B.F., and Parkhurst D.L., 1990. Revised chemical equilibrium data for major water-mineral reactions and their limitations, in Bassett, R.L. and Melchior, D. eds., Chemical modeling in aqueous systems II: Washington D.C., American Chemical Society Symposium Series 416, p. 398-413. 36.696 (Ref.: Internal calculation)
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.
Reaction properties

Gibbsite(mc) + 3H+ ⇌ Al+3 + 3H2O

298.15 K, 1 bar log10K: 9.35 ΔH°r:-102510 J·mol-1 (Ref.: 90nor/plu) Nordstrom D.K., Plummer L.N., Langmuir D., Busenberg E., May H.M., Jones B.F., and Parkhurst D.L., 1990. Revised chemical equilibrium data for major water-mineral reactions and their limitations, in Bassett, R.L. and Melchior, D. eds., Chemical modeling in aqueous systems II: Washington D.C., American Chemical Society Symposium Series 416, p. 398-413.
T(°C) 0 25 60 100 150 200 250 300
log10K 11.02 9.35 7.50 5.88 4.33 3.13 2.12 1.21
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-514.237606 -0.076453 31161.905855 184.481255 -1299560.774240