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Mineral speciesFormula
 ChloritoidFeAl2SiO5(OH)2 
Mineralogy
Family: Chloritoid group 
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 
Geological context
High temperature: Stable at around 400C and more. 
Geological context: Metamorphic phyllites, schists and marbles 
Thermodynamics
Individual properties
Molar weight: 251.907 g/mol  ΔGºf-2,962,146 J/mol ref.  Sº: 176.15 J/mol/K ref. 
  ΔHºf-3,193,300 J/mol ref.  Cp: 210.89 J/mol/K ref. 
Reaction properties
Chemical reaction:  Chloritoid + 8H+ = 2Al+3 + Fe+2 + H4SiO4 + 3H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -1.26859883e+3   -2.08003118e-1   7.86344894e+4   4.55473479e+2   -3.41212180e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)21.78
ΔH°r-292,184 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  26.45   21.78   16.39   11.44   6.45   2.33   -1.30   -4.69 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:253.68 J/mol/K 
b:71.67 J/mol/K2 
c:-57.03 J.K/mol 

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