Nesquehonite(alpha)

Formula : MgCO3:3H2O

Family: 
Carbonates
Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/n
Dana class: 
13.1.5.1 (13) Acid Carbonates (13.1) with miscellaneous formulae (13.1.5)Dana Group
High temperature: 
Stable under a normal atmospheric conditions.
Geological context: 
A very rare mineral, as an alteration mineral usually formed in coal mines and in serpentine masses. Stable under a normal atmospheric conditions.

Dernière mise à jour le 25.01.2021

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
 V°
cm3·mol-1
 ΔGºf
J·mol-1
 ΔHºf
J·mol-1
 Sº
J·mol-1·k-1
 CP
J·mol-1·K-1
138.360 74.790 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp. -1723781 (Ref.: Internal calculation) -1977300 (Ref.: 73rob/hem) Hemingway B. S. and Robie R. A., 1973. A calorimetric determination of the standard enthalpies of formation of huntite, CaMg3(CO3)4, and artinite, Mg2(OH)2CO3 z 3 H2O, and their standard Gibbs free energies of formation. J. Res. U.S. Geol. Survey, 1, pp. 535-541. 195.600 (Ref.: 72rob/hem) Robie R.A. and Hemingway B.S., 1972. The heat capacities at low-temperatures and entropies at 298.15 K of nesquehonite, MgCO3 :3H2O, and hydromagnesite. Am. Mineral., 57, pp. 1768-1781. 239.35 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp.
CP(T) = a + b·T + ·c·T-2 (T in Kelvin)
a
J·mol-1·K-1
 b * 103
J·mol-1·K-2
 c * 10-5
J·K·mol-1
 Maier Kelley Ref.
-6588.96 16314.10 1746.09 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp.
Reaction properties

Nesquehonite(alpha) + H+ ⇌ HCO3- + Mg+2 + 3H2O

298.15 K, 1 bar log10K: 5.23 ΔH°r:-37120 J·mol-1 (Ref.: 73rob/hem) Hemingway B. S. and Robie R. A., 1973. A calorimetric determination of the standard enthalpies of formation of huntite, CaMg3(CO3)4, and artinite, Mg2(OH)2CO3 z 3 H2O, and their standard Gibbs free energies of formation. J. Res. U.S. Geol. Survey, 1, pp. 535-541.
T(°C) 0 25 60 100 150 200 250 300
log10K 5.82 5.23 4.52 3.72 2.48 0.73 -1.71 -4.97
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-3106.995955 -0.568636 150827.274797 1155.571716 -7422143.945143