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Mineral speciesFormula
 CassiteriteSnO2 
Mineralogy
Family: Rutile Group 
Space group: Tetragonal - Ditetragonal Dipyramidal H-M Symbol (4/m 2/m 2/m) Space Group: P 4/mnm 
Dana class: 4.4.1.5 (4)Simple Oxides 4.4)with a cation charge of 4+ (A++++ O2) (4.4.1)Rutile group (Tetragonal: P4/mnm) 
Geological context
High temperature: Possible stability around 100C in laboratory experiments, in a natural environnement : hydrothermal and present in magmatic rocks during late pneumatolitic stage; but some data allows to suppose a cassiterite stable during the weathering stage of tin sul 
Geological context: Occurs in granite pegmatites and alluvial placer deposits. 
Thermodynamics
Individual properties
Molar weight: 150.709 g/mol  ΔGºf-515,826 J/mol ref.  Sº: 49.04 J/mol/K ref. 
  ΔHºf-577,630 J/mol ref.  Cp: 53.22 J/mol/K ref. 
Reaction properties
Chemical reaction:  Cassiterite + 2H+ = Sn+2 + 0.5O2 + H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -1.95559516e+2   -3.03148796e-2   -4.88233361e+3   7.28590358e+1   -4.23834603e+5 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)-45.46
ΔH°r276,957 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  -49.88   -45.46   -40.34   -35.61   -30.93   -27.22   -24.22   -21.78 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:76.04 J/mol/K 
b:7.36 J/mol/K2 
c:-22.24 J.K/mol 

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