Cristobalite(beta)

Formula : SiO2

Family: 
Space group: 
Tetragonal - Trapezohedral HM symbol (4 2 2) Space Group: P 41212
Dana class: 
75.1.1.1
High temperature: 
Above approximately 1470C to the melting point of silica round 1713C.
Geological context: 
Present in volcanic rocks, it form from molten rock at temperatures above approximately 1470 degrees Celsius to the melting point of silica (around 1713C)

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
60.084 27.440 -852639 -906290 44.013 64.88
Reaction properties

Cristobalite(beta) + 2H2O ⇌ H4SiO4

298.15 K, 1 bar log10K: -3.10 ΔH°r: 16756 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K -3.37 -3.10 -2.80 -2.52 -2.25 -2.04 -1.87 -1.73