Gibbsite(am)

Formula : Al(OH)3

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. -1138697 (Ref.: Internal calculation) -1276120 (Ref.: 93bar) Barin, I. (1993) Thermochemical Data of Pure Substances, Weinheim, FRG, VCH. 71.130 (Ref.: 93bar) Barin, I. (1993) Thermochemical Data of Pure Substances, Weinheim, FRG, VCH.
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(am) + 3H+ ⇌ Al+3 + 3H2O

298.15 K, 1 bar log10K: 10.58 ΔH°r:-119770 J·mol-1 (Ref.: 93bar) Barin, I. (1993) Thermochemical Data of Pure Substances, Weinheim, FRG, VCH.
T(°C) 0 25 60 100 150 200 250 300
log10K 12.52 10.58 8.41 6.49 4.67 3.24 2.05 0.98
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-516.036216 -0.076453 32063.453001 184.481255 -1299560.774240