Vermiculite SO

Formula : Ca0.445(Si2.778Al1.222)(Al0.216Mg2.475Fe0.254)O10(OH)2

Space group: 
Monoclinic - Prismatic HM symbol (2/m) Space Group: C 2/m
Dana class: 
71.3.1b.2VIII- 71 Phyllosilicate Minerals ; 71.3 Phyllosilicates Phyllosilicate Sheets of Six-Membered Rings with 2:1 clays ; 71.3.1b Smectite group (Trioctahedral Smectites)
High temperature: 
Low temperature mineral. At higher temperatures(> 500C), detachment of (OH) ions takes place.
Geological context: 
An alteration product of biotite or phlogopite, by weathering or hydrothermal action. Formed at the contact between felsic and ma_c or ultrama_c rocks such as pyroxenites and dunites; in carbonatites and metamorphosed limestones; a clayey constituent of soils.

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
403.004 148.360 (Ref.: 13gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Horiuchi, K., Yamamura, Y., Saito, K., Kawaji, H., Warmont, F., Greneche, J.-M., Vieillard, P., Fialips, C.I., Giffaut, E., Gaucher, E.C., 2013. Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements. American Mineralogist 98, 1834-1847. -5666172 (Ref.: Internal calculation) -6034410 (Ref.: 13gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Horiuchi, K., Yamamura, Y., Saito, K., Kawaji, H., Warmont, F., Greneche, J.-M., Vieillard, P., Fialips, C.I., Giffaut, E., Gaucher, E.C., 2013. Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements. American Mineralogist 98, 1834-1847. 325.770 (Ref.: 13gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Horiuchi, K., Yamamura, Y., Saito, K., Kawaji, H., Warmont, F., Greneche, J.-M., Vieillard, P., Fialips, C.I., Giffaut, E., Gaucher, E.C., 2013. Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements. American Mineralogist 98, 1834-1847. 346.97 (Ref.: 13gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Horiuchi, K., Yamamura, Y., Saito, K., Kawaji, H., Warmont, F., Greneche, J.-M., Vieillard, P., Fialips, C.I., Giffaut, E., Gaucher, E.C., 2013. Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements. American Mineralogist 98, 1834-1847.
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.
347.26 274.68 -73.06 (Ref.: 13gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Horiuchi, K., Yamamura, Y., Saito, K., Kawaji, H., Warmont, F., Greneche, J.-M., Vieillard, P., Fialips, C.I., Giffaut, E., Gaucher, E.C., 2013. Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements. American Mineralogist 98, 1834-1847.
Reaction properties

Vermiculite SO + 10.888H+ ⇌ 1.438Al+3 + 0.445Ca+2 + 0.226Fe+3 + 2.475Mg+2

298.15 K, 1 bar log10K: 45.90 ΔH°r:-457396 J·mol-1 (Ref.: 13gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Horiuchi, K., Yamamura, Y., Saito, K., Kawaji, H., Warmont, F., Greneche, J.-M., Vieillard, P., Fialips, C.I., Giffaut, E., Gaucher, E.C., 2013. Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements. American Mineralogist 98, 1834-1847.
T(°C) 0 25 60 100 150 200 250 300
log10K 53.12 45.90 37.42 29.62 21.86 15.58 10.18 5.23
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2871.562308 -0.412707 184398.486658 1022.750485 -9661820.606534