Home > Data consultation > Mineral species
 
Mineral speciesFormula
 AndalusiteAl2SiO5 
Mineralogy
Family: Silicate, Disthene series 
Space group: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pnnm 
Dana class: Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O (52.2) with cations in [4] and >[4] coordination (52.2.2b) AL2SIO5 (Andalusite subgroup) 
Geological context
High temperature: Stable in the range of200 to 800C. Its stability depends also on pressure. 
Geological context: Metamorphic aluminous rocks, aluminous magmas 
Thermodynamics
Individual properties
Molar weight: 162.046 g/mol  ΔGºf-2,429,176 J/mol ref.  Sº: 92.89 J/mol/K ref. 
  ΔHºf-2,576,881 J/mol ref.  Cp: 122.37 J/mol/K ref. 
Reaction properties
Chemical reaction:  Andalusite + 6H+ = 2Al+3 + H4SiO4 + H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -9.55170234e+2   -1.59735583e-1   6.02363074e+4   3.41868318e+2   -2.57505922e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)16.20
ΔH°r-246,943 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  20.14   16.20   11.63   7.40   3.12   -0.45   -3.58   -6.50 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:172.84 J/mol/K 
b:26.33 J/mol/K2 
c:-51.85 J.K/mol 

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