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Mineral speciesFormula
 CarnalliteKMgCl3:6H2O 
Mineralogy
Family: Miscellaneous salts 
Space group: Orthorhombic - Dipyramidal HM symbol (2/m 2/m 2/m) Space Group: Pcna 
Dana class: 11.1.2.1 
Geological context
Geological context: Thought to form in saline marine deposits by reaction of pre-existing saline minerals with fluids high in potash. 
Thermodynamics
Individual properties
Molar weight: 277.852 g/mol  ΔGºf-2,529,666 J/mol ref.  Sº: 439.48 J/mol/K ref. 
  ΔHºf-2,944,700 J/mol ref.   
Reaction properties
Chemical reaction:  Carnallite = 3Cl- + K+ + Mg+2 + 6H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -2.40136907e+3   -3.56948023e-1   1.29770600e+5   8.72512978e+2   -7.29814892e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)4.34
ΔH°r9,340 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  4.20   4.34   4.55   4.82   5.16   5.38   5.37   4.87 

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