Monticellite

Formula : CaMgSiO4

Space group: 
Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P nma
Dana class: 
51.3.2.1 (51) Nesosilicate Insular SiO4 Groups Only (51.3)with all cations in octahedral [6] coordination (51.3.2) Monticellite - Kirschsteinite series
High temperature: 
More than 340C and it melts incongruently at 1499C to form MgO and a liquid
Geological context: 
Occurs in banded iron formations subjected to low-grade regional metamorphism and in MgO riche skarn. Monticellite is also present in kimberlites and in smelting byproducts.

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
156.466 51.470 -2145677 -2262825 110.458 123.06
Reaction properties

Monticellite + 4H+ ⇌ Ca+2 + Mg+2 + H4SiO4

298.15 K, 1 bar log10K: 30.09 ΔH°r: -208370 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 33.43 30.09 26.27 22.80 19.39 16.67 14.37 12.32