Ettringite(Cr)

Formula : Ca6Al2(OH)12(CrO4)3:26H2O

Family: 
Chromate
Space group: 
Hexagonal - Dihexagonal Dipyramidal H-M Symbol (6/m 2/m 2/m) Space Group: P 63/mmc
Dana class: 
31.10.2.1 (31) Hydrated Sulfates Containing Hydroxyl or Halogen (31.10) miscellaneous (31.10.2)Dana Group
High temperature: 
Chromium analog to ettringite
Geological context: 
see ettringite

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
1314.810 742.829 (Ref.: 70moo/tay) Moore A.E., Taylor H.F.W., 1970. Acta Cryst., B26, 386-393 -15132196 (Ref.: 00per/pal) Perkins R.B. and Palmer C.D., 2000. Solubility of Ca6[Al(OH)6]2(CrO4)3.26 H2O, the chromate analog of ettringite; 5-75C. Applied Geochem., 15, p. 1203-1218. -17330292 (Ref.: 00per/pal) Perkins R.B. and Palmer C.D., 2000. Solubility of Ca6[Al(OH)6]2(CrO4)3.26 H2O, the chromate analog of ettringite; 5-75C. Applied Geochem., 15, p. 1203-1218. 2315.100 (Ref.: Internal calculation) 2120.00 (Ref.: 00per/pal) Perkins R.B. and Palmer C.D., 2000. Solubility of Ca6[Al(OH)6]2(CrO4)3.26 H2O, the chromate analog of ettringite; 5-75C. Applied Geochem., 15, p. 1203-1218.
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.
2120.00 0.00 0.00 (Ref.: 00per/pal) Perkins R.B. and Palmer C.D., 2000. Solubility of Ca6[Al(OH)6]2(CrO4)3.26 H2O, the chromate analog of ettringite; 5-75C. Applied Geochem., 15, p. 1203-1218.
Reaction properties

Ettringite(Cr) + 12H+ ⇌ 2Al+3 + 6Ca+2 + 3CrO4-2 + 38H2O

298.15 K, 1 bar log10K: 60.28 ΔH°r:-503048 J·mol-1 (Ref.: 00per/pal) Perkins R.B. and Palmer C.D., 2000. Solubility of Ca6[Al(OH)6]2(CrO4)3.26 H2O, the chromate analog of ettringite; 5-75C. Applied Geochem., 15, p. 1203-1218.
T(°C) 0 25 60 100 150 200 250 300
log10K 68.23 60.28 50.92 42.17 33.20 25.49 18.25 10.59
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-6462.793963 -1.002953 373726.255629 2340.851252 -19882336.950165