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Mineral speciesFormula
 Au(element)Au 
Mineralogy
Family: Metal 
Space group: Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F m3m 
Dana class: 1.1.1.1 (1) Native Elements (1.1) with metallic elements other than the platinum group (1.1.1) Gold group 
Geological context
High temperature: The richest electrum in silver is the in temperature : from room temperature to around250C. 
Geological context: Quartz veins and alluvial deposits.Two ways are possible to precipitate gold: i, from the weathering of primary gold trace-bearing minerals; ii, as electrum from the hydrothermal solution. Electrum is an alliage of gold and silver. 
Thermodynamics
Individual properties
Molar weight: 196.967 g/mol  ΔGºf0 J/mol ref.  Sº: 47.49 J/mol/K ref. 
  ΔHºf0 J/mol ref.  Cp: 25.23 J/mol/K ref. 
Reaction properties
Chemical reaction:  Au(element) + 0.75O2 + 3H+ = Au+3 + 1.5H2O 
log10(Keq) = A + B.T + C.T-1 + D.log10(T) + E.T−2 (with T expressed in Kelvin)
A B C D E
 -6.24419378e+2   -9.83684669e-2   3.38506509e+4   2.22655186e+2   -1.97157287e+6 
Van t'Hoff
@ 25°C, 1 bar: log 10(Keq)-11.45
ΔH°r49,202 J/mol ref.
T (ºC) : 0 25 60 100 150 200 250 300
log 10(Keq):  -11.31   -11.45   -11.66   -11.92   -12.26   -12.62   -13.06   -13.60 
Maier Kelley
Cp(T) = a + b*10-3T + C*105T-2 (with T expressed in Kelvin)  ref.
a:23.68 J/mol/K 
b:5.19 J/mol/K2 
c:0.00 J.K/mol 

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