Picromerite

Formula : K2Mg(SO4)2:6H2O

Family: 
Sulfates
Space group: 
Monoclinic - Prismatic HM symbol (2/m) Space Group: P 21/a
Dana class: 
29.3.6.1VI- 29 Hydrated Acid and Sulfates ; 29.3 Hydrated Acid and Sulfates where (A+)2 B (XO4)2 . x(H2O) ; 29.3.6

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
402.720 197.400 (Ref.: 63wyc) Wyckoff, R.W.G., 1963, Crystal Structures, Second edition, tome 4, Interscience Publishers, New York, p. 320-322. -3955961 (Ref.: 84har/mol) Harvie C.E., Moller N., and Weare J.H.. 1984, The prediction of mineral solubilities in natural waters: The Na-K-Mg-Ca-H-Cl-SO4-OH-HCO3-CO3-CO2-H2O system to high ionic strengths at 25 C. Geochimica Cosmochimica Acta, 48, pp. 723-751. -4538430 (Ref.: 74nau/ryz) Naumov G.B., Ryzhenko B.N., and Khodakovsky I.L., 1974. Handbook of Thermodynamic Data. U.S. Geol. Surv.WRD 74 001, 328 pp. 492.671 (Ref.: Internal calculation)
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

Picromerite ⇌ 2K+ + Mg+2 + 2SO4-2 + 6H2O

298.15 K, 1 bar log10K: -4.32 ΔH°r:33490 J·mol-1 (Ref.: 74nau/ryz) Naumov G.B., Ryzhenko B.N., and Khodakovsky I.L., 1974. Handbook of Thermodynamic Data. U.S. Geol. Surv.WRD 74 001, 328 pp.
T(°C) 0 25 60 100 150 200 250 300
log10K -4.89 -4.32 -3.71 -3.10 -2.51 -2.15 -2.17 -2.88
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-3349.681349 -0.495780 182181.770819 1212.817756 -10569863.323876