Titanite

Formula : CaTiSiO5

Family: 
Oxides
Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/a
Dana class: 
52.4.3.1 (52) Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O (52.4) with cations in [6] and/or > [6] coordination (52.4.3) Titanite group
High temperature: 
Its stability rangesfrom 300C (prehnite facies) to more than 1200C. It depends on TiO2+ versus AlF2+ substution.
Geological context: 
A common accessory mineral in intermediate and felsic plutonic rocks, pegmatites, and alpine veins. In gneisses, schists, and some skarns.

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
196.031 55.650 (Ref.: 78rob/hem,92cjoh) -2457468 (Ref.: 78rob/hem,92cjoh) -2599029 (Ref.: Internal calculation) 129.202 (Ref.: 78rob/hem,92cjoh) 138.99 (Ref.: 78rob/hem,92cjoh)
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.
176.71 23.87 -39.85 (Ref.: 78rob/hem,92cjoh)
Reaction properties

Titanite + 2H+ + 3H2O ⇌ Ca+2 + H4SiO4 + Ti(OH)4

298.15 K, 1 bar log10K: 0.99 ΔH°r:-60702 J·mol-1 (Ref.: Internal calculation)
T(°C) 0 25 60 100 150 200 250 300
log10K 2.05 0.99 0.05 -0.42 -0.40 0.01 0.63 1.30
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1118.222166 -0.122151 64584.624261 393.909706 -3172860.451667