Huntite

Formula : CaMg3(CO3)4

Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c
Dana class: 
65.1.3a.1 (65) Inosilicate Single-Width Unbranched Chains, W=1 (65.1)with chains P=2 (65.1.3a) C2/c clinopyroxenes (Ca clinopyroxenes)
High temperature: 
It is a low temperature mineral, its stablity at room temperature is possible.
Geological context: 
It is a low temperature mineral, its stability at room temperature is possible.Occurs as a cave carbonate in areas where the country rocks are magnesium-rich; as a near-surface weathering product of magnesium-rich rocks such as brucite, marbles, dolomites, serpentinites, or magnesite; as a diagenetic mineral in recent sediment sequences; and as a sabkha mineral associated with evaporitic magnesite in desert.

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
353.029 122.900 -4026422 -4352580 299.533 309.43
Reaction properties

Huntite + 4H+ ⇌ 4HCO3- + Ca+2 + 3Mg+2

298.15 K, 1 bar log10K: 42.03 ΔH°r: -351140 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 47.54 42.03 35.42 29.08 22.40 16.54 11.04 5.36