Anthophyllite

Formula : Mg7Si8O22(OH)2

Space group: 
Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P nma
Dana class: 
66.1.2.2 (66) Inosilicate Double-Width Unbranched Chains, W=2 (66.1) Dana Type (66.1.2) Group 1, the Mg-Fe-Mn-Li amphiboles (Orthorhombic)
High temperature: 
Anthophyllite is stable from 200C to about 700C.
Geological context: 
Occurs from medium- or high-grade metamorphism, in amphibolites, gneisses, metaquartzites, iron formations, granulites, and schists derived from argillaceous sediments, ultramafic, or mafic igneous rocks; also a retrograde reaction product.

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
780.820 265.400 -11343357 -12070000 534.500 663.01
Reaction properties

Anthophyllite + 14H+ + 8H2O ⇌ 7Mg+2 + 8H4SiO4

298.15 K, 1 bar log10K: 73.74 ΔH°r: -601914 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 83.43 73.74 62.76 52.91 43.32 35.67 29.19 23.29