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Mineral speciesFormula
 AndraditeCa3Fe2Si3O12 
Mineralogy
Family: Garnet Group 
Space group: Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: I a3d 
Dana class: 51.4.3b.1 (51) Nesosilicate Insular SiO4 Groups Only (51.4) with cations in [6] and >[6] coordination (51.4.3b) Garnet group (Ugrandite series) 
Geological context
High temperature: High temperature mineral. 
Geological context: Igneous and metamorphic rocks. 
Thermodynamics
Individual properties
Molar weight: 508.177 g/mol  ΔGºf-5,425,891 J/mol ref.  Sº: 293.42 J/mol/K ref. 
  ΔHºf-5,775,718 J/mol ref.  Cp: 349.14 J/mol/K ref. 
Reaction properties
Chemical reaction:  Andradite + 12H+ = 3Ca+2 + 2Fe+3 + 3H4SiO4 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -1.73909559e+3   -2.86483788e-1   1.03745004e+5   6.30730215e+2   -4.47857981e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)33.77
ΔH°r-137,101 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  39.15   33.77   27.63   22.03   16.44   11.82   7.72   3.80 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:475.02 J/mol/K 
b:65.42 J/mol/K2 
c:-129.24 J.K/mol 

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