Nontronite(K)

Formula : K0.34Fe1.67Al0.67Si3.66O10(OH)2

Space group: 
Monoclinic - Prismatic HM symbol (2/m) Space Group: C 2/m
Dana class: 
71.3.1a.3VIII- 71 Phyllosilicate Minerals ; 71.3 Phyllosilicates Phyllosilicate Sheets of Six-Membered Rings with 2:1 clays ; 71.3.1a Smectite group (Dioctahedral Smectites)
High temperature: 
Low temperature mineral. At higher temperatures(> 500C), detachment of (OH) ions takes place.
Geological context: 
Nontronite has been formed by the alteration of eruptive igneous rocks. Nontronite is found both in mineral veins (often with opal and quartz) and as an alteration product of volcanic glasses.

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
421.437 132.850 (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. -4638472 (Ref.: Internal calculation) -4994270 (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. 323.660 (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. 334.23 (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.
334.23 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

Nontronite(K) + 7.36H+ + 2.64H2O ⇌ 0.67Al+3 + 1.67Fe+3 + 0.34K+

298.15 K, 1 bar log10K: -3.98 ΔH°r:-118855 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 -2.22 -3.98 -6.26 -8.45 -10.65 -12.48 -14.16 -15.86
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2454.493112 -0.333653 149913.910315 868.649521 -9088011.878216