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Mineral speciesFormula
 GrossularCa3Al2Si3O12 
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.2 (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: Grossular is stable at high temperature more than 400C, its stability depends also on pressure. 
Geological context: Contact metasomatic deposits. 
Thermodynamics
Individual properties
Molar weight: 450.446 g/mol  ΔGºf-6,279,652 J/mol ref.  Sº: 260.10 J/mol/K ref. 
  ΔHºf-6,640,000 J/mol ref.  Cp: 327.85 J/mol/K ref. 
Reaction properties
Chemical reaction:  Grossular + 12H+ = 2Al+3 + 3Ca+2 + 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
 -1.75390828e+3   -2.92180283e-1   1.10669030e+5   6.34931682e+2   -4.61402210e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)49.36
ΔH°r-449,383 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  56.55   49.36   41.08   33.48   25.86   19.58   14.09   8.98 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:435.21 J/mol/K 
b:71.18 J/mol/K2 
c:-114.30 J.K/mol 

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