Voltaite

Formula : K2Fe9(SO4)12:18H2O

Family: 
Sulfates
Space group: 
Isometric - Hexoctahedral HM symbol (4/m -3 2/m) Space Group: F d3c
Dana class: 
29.9.1.1VI- 29 Hydrated Acid and Sulfates ; 29.9 Hydrated Acid and Sulfates with miscellaneous formulae ; 29.9.1

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
2057.860 -14497715 (Ref.: Internal calculation) -16860000 (Ref.: 02hem/sea) Hemingway, B.S., Seal, R.R., II, and Chou, I-M. (2002) Thermodynamic data for modeling acid mine drainage problems. Part I. Selected soluble iron-sulfate minerals. U.S. Geological Survey Open File Report 02 - 161, 13 p. 1959.000 (Ref.: 02hem/sea) Hemingway, B.S., Seal, R.R., II, and Chou, I-M. (2002) Thermodynamic data for modeling acid mine drainage problems. Part I. Selected soluble iron-sulfate minerals. U.S. Geological Survey Open File Report 02 - 161, 13 p.
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

Voltaite ⇌ 5Fe+2 + 2K+ + 12SO4-2 + 4Fe+3 + 18H2O

298.15 K, 1 bar log10K: -38.23 ΔH°r:-347300 J·mol-1 (Ref.: 02hem/sea) Hemingway, B.S., Seal, R.R., II, and Chou, I-M. (2002) Thermodynamic data for modeling acid mine drainage problems. Part I. Selected soluble iron-sulfate minerals. U.S. Geological Survey Open File Report 02 - 161, 13 p.
T(°C) 0 25 60 100 150 200 250 300
log10K -33.22 -38.23 -45.16 -52.43 -61.03 -69.94 -80.36 -94.42
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-21081.147805 -3.238027 1167409.103857 7617.162182 -67145558.314906