Edenite(alpha)

Formula : Na(Ca2Mg5)(AlSi7)O22(OH)2

Family: 
Amphiboles
Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
Dana class: 
66.1.3a.10 (66) Inosilicate Double-Width Unbranched Chains, W=2 (66.1) Dana Type (66.1.3a) Group 2, the calcic amphiboles
High temperature: 
Stability of amphibole ranges between 300C to 800C. It depends strongly on the figacity of water and pressure.
Geological context: 
In intermediate plutonic igneous and medium-grade metamorphic rocks, as amphibolites and marbles.

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
834.252 271.000 (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. -11880543 (Ref.: Internal calculation) -12589150 (Ref.: 97got) Gottschalk M. (1997) Internally consistent thermodynamic data set for rock forming minerals in the system SiO2-TiO2-Al2O3-Fe2O3-CaO-MgO-FeO-K2O-Na2O-H2O-CO2: an alternative approach. European Journal of Mineralogy, 9, p. 175-223. 673.624 (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. 679.88 (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.
835.59 204.10 -192.51 (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

Edenite(alpha) + 18H+ + 4H2O ⇌ Al+3 + 2Ca+2 + 5Mg+2

298.15 K, 1 bar log10K: 81.95 ΔH°r:-679296 J·mol-1 (Ref.: 97got) Gottschalk M. (1997) Internally consistent thermodynamic data set for rock forming minerals in the system SiO2-TiO2-Al2O3-Fe2O3-CaO-MgO-FeO-K2O-Na2O-H2O-CO2: an alternative approach. European Journal of Mineralogy, 9, p. 175-223.
T(°C) 0 25 60 100 150 200 250 300
log10K 92.58 81.95 69.31 57.71 46.29 37.14 29.35 22.21
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-5462.300890 -0.752420 350513.356888 1944.451075 -19420000.128348