Xonotlite

Formula : Ca6Si6O17(OH)2

Space group: 
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/a
Dana class: 
66.3.1.1 (66) Inosilicate Double-Width Unbranched Chains, W=2 (66.3 )with chains P>2 (66.3.1)P=3
High temperature: 
High temperature mineral in natural environment but posible at room temperature
Geological context: 
Xonotlite can be formed experimentally by the decomposition of tobermorite, by the dehydration of truscottite and gyrolite, or by the hydration of wollastonite. It occurs, in hornfels near limestone layers, associated with intrusive mafic bodies and as veinlets in serpentine or contact zones.

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
714.985 256.900 (Ref.: 56den/tay) Dent, L. S., and Taylor, H. F. W., 1956, The dehydration of Xonotlite: Acta Crystallographica, v. 9, p. 1002-1004. -9465305 (Ref.: 10abla/bou) Blanc, Ph.; Bourbon, X.; Lassin, A.; Gaucher, E.C. 2010 - Chemical model for cement-based materials: Temperature dependence of thermodynamic functions for nanocrystalline and crystalline C-S-H phases. Cement and Concrete Research, 40, p. 851-867 -10022150 (Ref.: 56new) Newman, E., 1956., Heats. of Formation of Xonotlite, Hillebrandite, and Foshagite: Journal of Research of the National Bureau of. Standards, v. 57, p. 27-30. 574.356 (Ref.: Internal calculation) 628.64 (Ref.: 10abla/bou) Blanc, Ph.; Bourbon, X.; Lassin, A.; Gaucher, E.C. 2010 - Chemical model for cement-based materials: Temperature dependence of thermodynamic functions for nanocrystalline and crystalline C-S-H phases. Cement and Concrete Research, 40, p. 851-867
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.
628.64 0.00 0.00 (Ref.: 10abla/bou) Blanc, Ph.; Bourbon, X.; Lassin, A.; Gaucher, E.C. 2010 - Chemical model for cement-based materials: Temperature dependence of thermodynamic functions for nanocrystalline and crystalline C-S-H phases. Cement and Concrete Research, 40, p. 851-867
Reaction properties

Xonotlite + 12H+ + 5H2O ⇌ 6Ca+2 + 6H4SiO4

298.15 K, 1 bar log10K: 91.33 ΔH°r:-559866 J·mol-1 (Ref.: 56new) Newman, E., 1956., Heats. of Formation of Xonotlite, Hillebrandite, and Foshagite: Journal of Research of the National Bureau of. Standards, v. 57, p. 27-30.
T(°C) 0 25 60 100 150 200 250 300
log10K 100.07 91.33 80.87 71.16 61.53 53.81 47.33 41.50
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-3825.133768 -0.517229 256808.092331 1362.853091 -14485119.707065