Pentahydrite

Formula : MgSO4:5H2O

Family: 
Sulfates
Space group: 
Triclinic Pedial or Pinacoidal HM symbol (1 or -1) Space Group: P1
Dana class: 
29.6.7.3VI- 29 Hydrated Acid and Sulfates ; 29.6 Hydrated Acid and Sulfates where A XO4 . x(H2O) ; 29.6.7 Chalchanthite Group (Triclinic: P1_)

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
210.445 109.600 (Ref.: 63wyc) Wyckoff, R.W.G., 1963, Crystal Structures, Second edition, tome 4, Interscience Publishers, New York, p. 320-322. -2392388 (Ref.: 80har/wea) Harvie C.E., and Weare J.H., 1980. The prediction of mineral soluhilities in natural waters: the Na K Mg Ca Cl SO4 H2O system from zero to high concentration at 25C. Geochimica et Cosmochimica Acta, 44, p. 981 997. -2791303 (Ref.: Internal calculation) 303.340 (Ref.: 99yun/glu) Yungman V.S., and Glusko V.P., 1999. Thermal constants of substances. Wiley, Begell House, New York.
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.
Reaction properties

Pentahydrite ⇌ Mg+2 + SO4-2 + 5H2O

298.15 K, 1 bar log10K: -1.27 ΔH°r:-14187 J·mol-1 (Ref.: Internal calculation)
T(°C) 0 25 60 100 150 200 250 300
log10K -1.04 -1.27 -1.49 -1.59 -1.59 -1.57 -1.66 -2.05
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1806.399252 -0.261373 98854.325556 652.012202 -5499662.703393