Andalusite

Formula : Al2SiO5

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)
High temperature: 
Stable in the range of200 to 800C. Its stability depends also on pressure.
Geological context: 
Metamorphic aluminous rocks, aluminous magmas

Dernière mise à jour le 19.12.2017

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
cm3·mol-1
ΔGºf
kJ·mol-1
ΔHºf
kJ·mol-1
J·mol-1·k-1
CP
J·mol-1·K-1
162.046 51.530 -2.429.176 -2.576.881 92.885 122.37
Reaction properties

Andalusite + 6H+ ⇌ 2Al+3 + H4SiO4 + H2O

298.15 K, 1 bar log10K: 16.20 ΔH°r: -246943 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 20.14 16.20 11.63 7.40 3.12 -0.45 -3.58 -6.50