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Mineral speciesFormula
 Chamosite(Daphnite)Fe5Al(AlSi3)O10(OH)8 
Mineralogy
Family: Chlorite Group 
Space group: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m 
Dana class: 71.4.1.4 (71)Phyllosilicate Sheets of Six-Membered Rings (71.4)interlayered 1:1, 2:1, and octahedra (71.4.1)Chlorite group (Tri-Dioctahedral) 
Geological context
High temperature: Metamorphosed iron deposits : lower limit of stability is probabily near ambiant, upper stability limit around 650C. 
Geological context: Contact, hydrothermal, and regional metamorphism of mafic minerals. A product of low-grade metamorphism of Al, Mg-rich rocks. 
Thermodynamics
Individual properties
Molar weight: 713.507 g/mol  ΔGºf-6,506,859 J/mol ref.  Sº: 559.40 J/mol/K ref. 
  ΔHºf-7,120,845 J/mol ref.  Cp: 574.76 J/mol/K ref. 
Reaction properties
Chemical reaction:  Chamosite(Daphnite) + 16H+ = 2Al+3 + 5Fe+2 + 3H4SiO4 + 6H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -2.73000947e+3   -4.30881390e-1   1.65103504e+5   9.84250311e+2   -7.39235005e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)47.59
ΔH°r-504,518 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  55.69   47.59   38.34   29.97   21.68   14.91   8.99   3.42 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:599.55 J/mol/K 
b:372.80 J/mol/K2 
c:-120.85 J.K/mol 

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