Chloritoid

Formula : FeAl2SiO5(OH)2

Space group: 
Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1
Dana class: 
52.3.3.1 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O (52.3) with cations in [6] coordination only (52.3.3) Chloritoid group
High temperature: 
Stable at around 400C and more.
Geological context: 
Metamorphic phyllites, schists 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
251.907 69.800 (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. -2962146 (Ref.: Internal calculation) -3193300 (Ref.: 87woo/gar) Woods T. L. and Garrels R. M. (1987) Thermodynamic values at low temperature for natural inorganic materials. An uncritical summary. Oxford University Press, New York. 176.146 (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. 210.89 (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.
253.68 71.67 -57.03 (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

Chloritoid + 8H+ ⇌ 2Al+3 + Fe+2 + H4SiO4 + 3H2O

298.15 K, 1 bar log10K: 21.79 ΔH°r:-289851 J·mol-1 (Ref.: 87woo/gar) Woods T. L. and Garrels R. M. (1987) Thermodynamic values at low temperature for natural inorganic materials. An uncritical summary. Oxford University Press, New York.
T(°C) 0 25 60 100 150 200 250 300
log10K 26.38 21.79 16.41 11.43 6.42 2.27 -1.37 -4.77
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1664.386189 -0.254489 104381.774745 594.288583 -5207161.679033