Thenardite

Formula : Na2SO4

Family: 
Sulfates
Space group: 
Orthorhombic - Dipyramidal HM symbol (2/m 2/m 2/m) Space Group: F ddd
Dana class: 
28.2.3.1VI- 28 Sulfate Minerals ; 28.2 Anhydrous Acid and Sulfates (A+)2 XO4 ; 28.2.2
High temperature: 
Supergene arid environments and chemical processes.
Geological context: 
Occurs as non-marine evaporite deposits in arid climates and alteration of alkali-ignous rocks protected from water; as oxidation product from slags from alkaline smelting.

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
142.043 53.330 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. -1269850 (Ref.: Internal calculation) -1387559 (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. 150.160 (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. 128.17 (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.
105.21 115.79 -10.28 (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

Thenardite ⇌ 2Na+ + SO4-2

298.15 K, 1 bar log10K: -0.34 ΔH°r:-2461 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 -0.37 -0.34 -0.47 -0.74 -1.21 -1.82 -2.61 -3.74
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1616.322933 -0.253239 89802.804248 586.412005 -5400469.399985