Sylvite

Formula : KCl

Family: 
Chlorides
Space group: 
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F m3m
Dana class: 
9.1.1.2 (9)Anhydrous and Hydrated Halides (9.1)where A X (9.1.1)Dana Group
High temperature: 
Sylvite is stable at room temperature but also found as precipitate from magmatic fluids.
Geological context: 
Occurs cheifly as extensive thick sedimentary deposits, also as sublimation products from volcanics gases, in fluid inclusions in hydrothemal systems, and as chlorure in many wastes.

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
74.551 37.524 (Ref.: 78hel/del) Helgeson, H.C., Delany, J.M, Nesbitt, H.W., and Bird, D.K., 1978. Summary and Critique of the Thermodynamic Properties of Rock Forming Minerals: Amer. J. Sci., 278A, 229 pp. -408752 (Ref.: Internal calculation) -436680 (Ref.: 98cha) Chase, M.W.J., 1998. NIST-JANAF Thermochemical Tables, Journal of Physical Chemistry Reference Data, Vol. 9, 4th Edition. National Institute of Standards and Technology, Washington DC, 1951 pp. 82.550 (Ref.: 78hel/del, 98cha) 51.29 (Ref.: 98cha) Chase, M.W.J., 1998. NIST-JANAF Thermochemical Tables, Journal of Physical Chemistry Reference Data, Vol. 9, 4th Edition. National Institute of Standards and Technology, Washington DC, 1951 pp.
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.
51.29 0.00 0.00 (Ref.: 98cha) Chase, M.W.J., 1998. NIST-JANAF Thermochemical Tables, Journal of Physical Chemistry Reference Data, Vol. 9, 4th Edition. National Institute of Standards and Technology, Washington DC, 1951 pp.
Reaction properties

Sylvite ⇌ Cl- + K+

298.15 K, 1 bar log10K: 0.87 ΔH°r:17460 J·mol-1 (Ref.: 98cha) Chase, M.W.J., 1998. NIST-JANAF Thermochemical Tables, Journal of Physical Chemistry Reference Data, Vol. 9, 4th Edition. National Institute of Standards and Technology, Washington DC, 1951 pp.
T(°C) 0 25 60 100 150 200 250 300
log10K 0.56 0.87 1.15 1.31 1.35 1.25 1.01 0.59
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-687.505006 -0.111459 37309.484614 251.582624 -2315949.249769