Anorthite

Formula : Ca(Al2Si2)O8

Space group: 
Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1,11
Dana class: 
76.1.3.6 (76) Tectosilicate Al-Si Framework (76.1) with Al-Si frameworks (76.1.3) Plagioclase series
High temperature: 
More than 300C for plagioclase (Na1-xCaxAl2-xSi2-xO8)
Geological context: 
Magmatic and metamorphic rocks and in some geothermal field. More than 300C for plagioclase (Na1-xCaxAl2-xSi2-xO8)

Dernière mise à jour le 11.06.2018

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
cm3·mol-1
ΔGºf
J·mol-1
ΔHºf
J·mol-1
J·mol-1·k-1
CP
J·mol-1·K-1
278.207 100.790 -4002095 -4227830 199.300 50.47
Reaction properties

Anorthite + 8H+ ⇌ 2Al+3 + Ca+2 + 2H4SiO4

298.15 K, 1 bar log10K: 25.31 ΔH°r: -314358 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 30.36 25.31 19.55 14.35 9.22 5.06 1.49 -1.80