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Mineral speciesFormula
 DiasporeAlO(OH) 
Mineralogy
Family: Diaspore - Goethite - Faitknechtite series 
Space group: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pbnm 
Dana class: 6.1.1.1 (6)Hydroxides and Oxides Containing Hydroxyl (6.1)where X+++O OH (6.1.1)Diaspore group (Orthorhombic, Pnma or Pnmd) 
Geological context
High temperature: From the ambiant to 450C in metamorphic terranes 
Geological context: Major constituent of most bauxite ores that are secondary deposits from supergene alteration. 
Thermodynamics
Individual properties
Molar weight: 59.988 g/mol  ΔGºf-922,740 J/mol ref.  Sº: 35.30 J/mol/K ref. 
  ΔHºf-1,001,300 J/mol ref.  Cp: 53.33 J/mol/K ref. 
Reaction properties
Chemical reaction:  Diaspore + 3H+ = Al+3 + 2H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -4.82018827e+2   -7.79313211e-2   2.99649588e+4   1.72375182e+2   -1.32574466e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)6.87
ΔH°r-108,760 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  8.60   6.87   4.86   3.01   1.16   -0.38   -1.73   -2.98 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:53.33 J/mol/K 
b:0.00 J/mol/K2 
c:0.00 J.K/mol 

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