Cronstedtite(Th)

Formula : Fe3SiAlO5(OH)4

Family: 
Pyroxenes
Space group: 
Trigonal - Ditrigonal Pyramidal H-M Symbol (3m) Space Group: P 31m
Dana class: 
71.1.2c.7 (71) Phyllosilicate Sheets of Six-Membered Rings (71.1) with 1:1 layers (71.1.2c) Serpentine group (Amesite subgroup)
High temperature: 
Cronstedtite is stable at low temperature in iron-rich medium.
Geological context: 
A low-temperature hydrothermal product in ore veins.

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
370.634 90.440 (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. -2628326 (Ref.: Internal calculation) -2916680 (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. 346.470 (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. 307.69 (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.
307.69 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

Cronstedtite(Th) + 10H+ ⇌ Al+3 + 2Fe+2 + H4SiO4 + Fe+3

298.15 K, 1 bar log10K: 96.64 ΔH°r:-738731 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 108.44 96.64 83.03 70.60 58.32 48.51 40.30 33.12
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2007.400626 -0.298539 146416.281735 716.057342 -6210720.288027