Laumontite

Formula : Ca(Al2Si4)O12:4H2O

Family: 
Zeolites
Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
Dana class: 
77.1.1.4 (77) Tectosilicate Zeolite group (77.1) true zeolites (77.1.1) Analcime and related species
High temperature: 
The structure of zeolite are very responsive in temperature and/or water-vapor pressure. Some "robust" zeolites can be heated to high temperatures and can be completely dehydrated while maintaining their original structure.
Geological context: 
occurs in a wide range of environments: secondary mineral in basalts and andesites, metamorphic rocks and granites, copper veins, Sedimentary-metamorphic- hydrothermally altered rocks, alteration product of cementious materials.

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
470.437 207.530 (Ref.: 97coo/alb) Coombs, D.S., Alberti, A., Armbruster, T., Artioli, G., Colella, C., Galli, E., Grice, J.D., Liebau, F., Mandarino, J.A., Minato, H., Nickel, E.H., Passaglia, E., Peacor, D.R., Quartieri, S., Rinaldi, R., Ross, M., Sheppard, R.A., Tillmanns, E., Vealini, G., 1997. Recommended nomenclature for zeolite minerals - report of the subcommittee on zeolites of the international mineralogical association, commission on new minerals and mineral names. Canadian Mineralogist, 35, 1571-1606. -6698359 (Ref.: Internal calculation) -7251000 (Ref.: 96kis/nav) Kiseleva I., Navrotsky A., Belitskii I. A., and Fursenko B. A. (1996) Thermochemistry and phase equilibria in calcium zeolites. American Mineralogist 81(5-6), 658-667 483.800 (Ref.: 09bla) Blanc P. (2009) - Thermochimie - Selection de constantes thermodynamiques pour les zeolites : version 2. Rapport final. Rapport BRGM/RP-57796-FR. 55 p. 503.70 (Ref.: 10vie) Vieillard P., 2010 - A predictive model for the entropies and heat capacities of zeolites. Eur. J. Mineral. 22, 823-836
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.
416.52 436.00 -38.06 (Ref.: 10vie) Vieillard P., 2010 - A predictive model for the entropies and heat capacities of zeolites. Eur. J. Mineral. 22, 823-836
Reaction properties

Laumontite + 8H+ ⇌ 2Al+3 + Ca+2 + 4H4SiO4

298.15 K, 1 bar log10K: 11.69 ΔH°r:-204244 J·mol-1 (Ref.: 96kis/nav) Kiseleva I., Navrotsky A., Belitskii I. A., and Fursenko B. A. (1996) Thermochemistry and phase equilibria in calcium zeolites. American Mineralogist 81(5-6), 658-667
T(°C) 0 25 60 100 150 200 250 300
log10K 14.81 11.69 7.83 4.19 0.52 -2.51 -5.22 -7.84
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2644.742924 -0.366842 164190.737001 939.000014 -9634347.273047