Bassanite

Formula : CaSO4:0.5H2O

Family: 
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 25.01.2021

THERMODYNAMICS

Reaction properties

Bassanite ⇌ Ca+2 + SO4-2 + 0.5H2O

298.15 K, 1 bar log10K: -3.92 ΔH°r:-17357 J·mol-1 (Ref.: Internal calculation)
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