Bassanite

Formula : CaSO4:0.5H2O

Space group: 
Orthorombic Space Group: Unk
Dana class: 
29.6.1.1VI- 29 Hydrated Acid and Sulfates ; 29.6 Hydrated Acid and Sulfates where A XO4 . x(H2O) ; 29.6.1
High temperature: 
Stable at around 80C from gypsum
Geological context: 
In cavities in leucite-tephrite blocks, 1906 eruption. Dehydrates at 130C. Hydrates to gypsum in a humid atmosphere.

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
145.149 106.080 -1437756 -1577897 130.540 119.45
Reaction properties

Bassanite ⇌ Ca+2 + SO4-2 + 0.5H2O

298.15 K, 1 bar log10K: -3.92 ΔH°r: -17358 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K -3.73 -3.92 -4.34 -4.93 -5.77 -6.72 -7.85 -9.29