I/S(ISCz-1)

Formula : (Ca0.092K0.439)(Si3.562Al0.438)(Al1.732Fe0.04Mg0.255)O10(OH)2

Space group: 
Monoclinic - Prismatic HM symbol (2/m) Space Group: C 2/m
Dana class: 
71.2.2d.2VIII- 71 Phyllosilicate Minerals ; 71.2 Phyllosilicates Phyllosilicate Sheets of Six-Membered Rings with 2:1 Layers ; 71.2.2d Mica Group (Hydromica subgroup)
High temperature: 
Low temperature mineral. At higher temperatures( 700C), micas can form in acid environments as long as excess potassium is available.
Geological context: 
Illites are the dominant clay minerals in shales and mudstones, and they also occur in other sediments such as limestones. The illites of sediments may have been deposited as such after their formation by surface weathering of silicates, principally feldspars, but in some occurrences they are derived by alterationof other clay minerals, during diagenesis.

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
381.882 137.130 (Ref.: 14bla/gai) Blanc, P., Gailhanou, H., Rogez, J., Mikaelian, G., Kawaji, H., Warmont, F., Grangeon, S., Greneche, J.M., Fialips, C.I., Giffaut, E., Gaucher, E.C., Claret, F., 2014, Thermodynamic properties of a chlorite and a berthierine by calorimetric methods: Physics and Chemistry of Minerals (accdepted) -5418621 (Ref.: Internal calculation) -5787220 (Ref.: 19gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Kawaji, H., Olives, J., Montouillout, V., Greneche, J.M., Vieillard, P., Gaucher, E.C., Fialips, C.I., Made, B., 2019. Thermodynamic properties of mixed-layer illite-smectite by calorimetric methods: Acquisition of the enthalpies of mixing of illite and smectite layers. The Journal of Chemical Thermodynamics 138, 78-97. 295.360 (Ref.: 19gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Kawaji, H., Olives, J., Montouillout, V., Greneche, J.M., Vieillard, P., Gaucher, E.C., Fialips, C.I., Made, B., 2019. Thermodynamic properties of mixed-layer illite-smectite by calorimetric methods: Acquisition of the enthalpies of mixing of illite and smectite layers. The Journal of Chemical Thermodynamics 138, 78-97. 306.04 (Ref.: 19gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Kawaji, H., Olives, J., Montouillout, V., Greneche, J.M., Vieillard, P., Gaucher, E.C., Fialips, C.I., Made, B., 2019. Thermodynamic properties of mixed-layer illite-smectite by calorimetric methods: Acquisition of the enthalpies of mixing of illite and smectite layers. The Journal of Chemical Thermodynamics 138, 78-97.
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.
236.14 422.80 -49.92 (Ref.: 19gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Kawaji, H., Olives, J., Montouillout, V., Greneche, J.M., Vieillard, P., Gaucher, E.C., Fialips, C.I., Made, B., 2019. Thermodynamic properties of mixed-layer illite-smectite by calorimetric methods: Acquisition of the enthalpies of mixing of illite and smectite layers. The Journal of Chemical Thermodynamics 138, 78-97.
Reaction properties

I/S(ISCz-1) + 7.752H+ + 2.248H2O ⇌ 2.17Al+3 + 0.092Ca+2 + 0.029Fe+3

298.15 K, 1 bar log10K: 10.95 ΔH°r:-217166 J·mol-1 (Ref.: 19gai/bla) Gailhanou, H., Blanc, P., Rogez, J., Mikaelian, G., Kawaji, H., Olives, J., Montouillout, V., Greneche, J.M., Vieillard, P., Gaucher, E.C., Fialips, C.I., Made, B., 2019. Thermodynamic properties of mixed-layer illite-smectite by calorimetric methods: Acquisition of the enthalpies of mixing of illite and smectite layers. The Journal of Chemical Thermodynamics 138, 78-97.
T(°C) 0 25 60 100 150 200 250 300
log10K 14.27 10.95 6.84 2.96 -0.98 -4.27 -7.22 -10.05
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2494.897991 -0.351226 155208.175523 885.628106 -9016899.813517