Akermanite

Formula : Ca2MgSi2O7

Space group: 
Tetragonal - Scalenohedral H-M Symbol (4 2m) Space Group: P 421m
Dana class: 
55.4.1.1 (55) Sorosilicate Si2O7 Groups, Generally with No Additional Anions (55.4) with cations in [8] and lower coordination(55.4.1) Melilite group
High temperature: 
High temperature mineral.
Geological context: 
A product of contact metamorphism of siliceous limestones and dolostones, and in rocks of the sanidinite facies. Also, forms from alkalic magmas rich in calcium and during smelting processes.

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
272.628 92.810 -3.679.251 -3.876.679 209.326 211.98
Reaction properties

Akermanite + 6H+ + H2O ⇌ 2Ca+2 + Mg+2 + 2H4SiO4

298.15 K, 1 bar log10K: 46.08 ΔH°r: -312880 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 51.11 46.08 40.34 35.13 30.00 25.89 22.42 19.32