Alunite(K)

Formula : KAl3(OH)6(SO4)2

Family: 
Space group: 
Trigonal Space Group: R 3m, R 3m
Dana class: 
30.2.4.1 (30)Anhydrous Sulfates Containing Hydroxyl or Halogen (30.2)where (A B)2 XO4 Zq (30.2.4) Alunite Group (Alunite Subgroup)
High temperature: 
Newly formed at a temperature less than 300C.
Geological context: 
Hydrothermal and supergene mineral

Dernière mise à jour le 11.06.2018

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
cm3·mol-1
ΔGºf
J·mol-1
ΔHºf
J·mol-1
J·mol-1·k-1
CP
J·mol-1·K-1
414.214 293.600 -4659302 -5170262 328.026 383.40
Reaction properties

Alunite(K) + 6H+ ⇌ 3Al+3 + K+ + 2SO4-2 + 6H2O

298.15 K, 1 bar log10K: -0.52 ΔH°r: -230738 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 2.99 -0.52 -5.00 -9.56 -14.71 -19.60 -24.55 -30.02