Hematite

Formula : Fe2O3

Family: 
Oxides
Space group: 
Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3c
Dana class: 
4.3.1.2 (4) Simple Oxides (4.3) with a cation charge of 3+ (A+++2 O3) (4.3.1) Corundum-Hematite group (Rhombohedral: R3c)
High temperature: 
It is stable in a wide range of temperature. Its is an anhydrous mineral and thus its stability is limited by the activity of the water in the medium.
Geological context: 
Hematite is a widespread mineral that occurs in magmatic, hydrothermal, metamorphic and sedimentary environment.

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
159.692 30.300 (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. -744249 (Ref.: Internal calculation) -826230 (Ref.: 90hem) Hemingway B. S. (1990) Thermodynamic properties for bunsenite, NiO, magnetite, Fe3O4, and hematite, Fe2O3, with comments on selected oxygen buffer reactions. American Mineralogist 75(7-8), 781-790. 87.404 (Ref.: 90hem) Hemingway B. S. (1990) Thermodynamic properties for bunsenite, NiO, magnetite, Fe3O4, and hematite, Fe2O3, with comments on selected oxygen buffer reactions. American Mineralogist 75(7-8), 781-790. 103.88 (Ref.: 90hem) Hemingway B. S. (1990) Thermodynamic properties for bunsenite, NiO, magnetite, Fe3O4, and hematite, Fe2O3, with comments on selected oxygen buffer reactions. American Mineralogist 75(7-8), 781-790.
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.
116.50 48.72 -24.13 (Ref.: 90hem) Hemingway B. S. (1990) Thermodynamic properties for bunsenite, NiO, magnetite, Fe3O4, and hematite, Fe2O3, with comments on selected oxygen buffer reactions. American Mineralogist 75(7-8), 781-790.
Reaction properties

Hematite + 6H+ ⇌ 2Fe+3 + 3H2O

298.15 K, 1 bar log10K: -0.04 ΔH°r:-129260 J·mol-1 (Ref.: 90hem) Hemingway B. S. (1990) Thermodynamic properties for bunsenite, NiO, magnetite, Fe3O4, and hematite, Fe2O3, with comments on selected oxygen buffer reactions. American Mineralogist 75(7-8), 781-790.
T(°C) 0 25 60 100 150 200 250 300
log10K 2.02 -0.04 -2.42 -4.61 -6.82 -8.69 -10.40 -12.09
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-942.810161 -0.152825 53792.155967 337.934992 -2514509.071854