Grossular

Formula : Ca3Al2Si3O12

Family: 
Garnet
Space group: 
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: I a3d
Dana class: 
51.4.3b.2 (51) Nesosilicate Insular SiO4 Groups Only (51.4) with cations in [6] and >[6] coordination (51.4.3b) Garnet group (Ugrandite series)
High temperature: 
Grossular is stable at high temperature more than 400C, its stability depends also on pressure.
Geological context: 
Contact metasomatic deposits, metamorphic contact marbles

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
450.446 125.300 (Ref.: 78hel/del,92ajoh) -6279652 (Ref.: Internal calculation) -6640000 (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. 260.100 (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. 327.85 (Ref.: 78hel/del,92ajoh)
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.
435.21 71.18 -114.30 (Ref.: 78hel/del,92ajoh)
Reaction properties

Grossular + 12H+ ⇌ 2Al+3 + 3Ca+2 + 3H4SiO4

298.15 K, 1 bar log10K: 49.37 ΔH°r:-442383 J·mol-1 (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.
T(°C) 0 25 60 100 150 200 250 300
log10K 56.33 49.37 41.13 33.46 25.76 19.41 13.88 8.73
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-2956.675440 -0.434106 188687.694641 1057.026958 -10038714.693750