Prehnite

Formula : Ca2Al2Si3O10(OH)2

Space group: 
Orthorhombic - Pyramidal H-M Symbol (mm2) Space Group: P 2cm
Dana class: 
72.1.3.1 (72) Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings (72.1) with 4-membered rings (72.1.3) Dana group
High temperature: 
Stability of prehnite ranges between 200Cto 450C.
Geological context: 
A secondary or hydrothermal mineral in veins and cavities in mafic volcanic rocks; less commonly in granite gneiss or syenite; a typical product of low-grade metamorphism.

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
412.384 141.100 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. -5822606 (Ref.: Internal calculation) -6199766 (Ref.: 98cha/kru) Chatterjee, N.D., Kruger, R., Haller, G., Olbricht, W., 1998. The Bayesian approach to an internally consistent thermodynamic database: theory, database, and generation of phase diagrams. Contributions to Mineralogy and Petrology 133, 149-168. 292.800 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. 330.57 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp.
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.
378.71 164.58 -86.41 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp.
Reaction properties

Prehnite + 10H+ ⇌ 2Al+3 + 2Ca+2 + 3H4SiO4

298.15 K, 1 bar log10K: 32.60 ΔH°r:-339617 J·mol-1 (Ref.: 98cha/kru) Chatterjee, N.D., Kruger, R., Haller, G., Olbricht, W., 1998. The Bayesian approach to an internally consistent thermodynamic database: theory, database, and generation of phase diagrams. Contributions to Mineralogy and Petrology 133, 149-168.
T(°C) 0 25 60 100 150 200 250 300
log10K 37.91 32.60 26.25 20.34 14.39 9.48 5.18 1.14
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2625.546493 -0.380419 165865.871913 936.420065 -9054968.136223