Saponite(FeCa)

Formula : Ca0.17Mg2FeAl0.34Si3.66O10(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: 
Saponite has been formed by the alteration of eruptive igneous rocks. Saponite occurs mainly associated with minerals veins, but also in amygdaloidal cavities in basalt along with celadonite.

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
417.246 145.150 (Ref.: 15bla/vie) Blanc, P., Vieillard, P., Gailhanou, H., Gaboreau, S., Gaucher, E.C., Fialips, C.I., Made, B., Giffaut, E., 2015. A generalized model for predicting the thermodynamic properties of clay minerals. American Journal of Science 315, 734-780. -5275212 (Ref.: Internal calculation) -5633570 (Ref.: 15bla/vie) Blanc, P., Vieillard, P., Gailhanou, H., Gaboreau, S., Gaucher, E.C., Fialips, C.I., Made, B., Giffaut, E., 2015. A generalized model for predicting the thermodynamic properties of clay minerals. American Journal of Science 315, 734-780. 337.850 (Ref.: 15bla/vie) Blanc, P., Vieillard, P., Gailhanou, H., Gaboreau, S., Gaucher, E.C., Fialips, C.I., Made, B., Giffaut, E., 2015. A generalized model for predicting the thermodynamic properties of clay minerals. American Journal of Science 315, 734-780. 339.50 (Ref.: 15bla/vie) Blanc, P., Vieillard, P., Gailhanou, H., Gaboreau, S., Gaucher, E.C., Fialips, C.I., Made, B., Giffaut, E., 2015. A generalized model for predicting the thermodynamic properties of clay minerals. American Journal of Science 315, 734-780.
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.
339.50 0.00 0.00 (Ref.: 15bla/vie) Blanc, P., Vieillard, P., Gailhanou, H., Gaboreau, S., Gaucher, E.C., Fialips, C.I., Made, B., Giffaut, E., 2015. A generalized model for predicting the thermodynamic properties of clay minerals. American Journal of Science 315, 734-780.
Reaction properties

Saponite(FeCa) + 7.36H+ + 2.64H2O ⇌ 0.34Al+3 + 0.17Ca+2 + Fe+2

298.15 K, 1 bar log10K: 26.57 ΔH°r:-250636 J·mol-1 (Ref.: 15bla/vie) Blanc, P., Vieillard, P., Gailhanou, H., Gaboreau, S., Gaucher, E.C., Fialips, C.I., Made, B., Giffaut, E., 2015. A generalized model for predicting the thermodynamic properties of clay minerals. American Journal of Science 315, 734-780.
T(°C) 0 25 60 100 150 200 250 300
log10K 30.45 26.57 21.88 17.57 13.36 10.02 7.20 4.61
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2535.634448 -0.337384 162363.852169 898.718355 -9386812.038081