Fluorite

Formula : CaF2

Family: 
Fluorides
Space group: 
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F m3m
Dana class: 
9.2.1.1 (9) Anhydrous and Hydrated Halides (9.2) where A (X)2 (9.2.1) Dana Group
High temperature: 
Fluorite is stable at low temperature but not at room temperature.
Geological context: 
Occurs widespread as common mineral in hydrothermal ore deposits; in cavities in sedimentary rocks; as hot spring deposit; in certain granites.

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
78.075 24.542 (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. -1175844 (Ref.: 04gar/muc) Alain Garand, Alfonso Mucci. The solubility of fluorite as a function of ionic strength and solution composition at 25C and 1 atm total pressure. Marine Chemistry, Volume 91, Issues 1-4, 15 November 2004, Pages 27-35 -1228261 (Ref.: Internal calculation) 68.576 (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. 71.12 (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.
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.
59.83 30.46 1.97 (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.
Reaction properties

Fluorite ⇌ Ca+2 + 2F-

298.15 K, 1 bar log10K: -10.51 ΔH°r:14561 J·mol-1 (Ref.: Internal calculation)
T(°C) 0 25 60 100 150 200 250 300
log10K -10.82 -10.51 -10.33 -10.35 -10.62 -11.12 -11.90 -13.07
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1649.680524 -0.266114 88752.675512 598.367246 -5314600.746853