Au(element)

Formula : Au

Family: 
Element
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
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.

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
196.967 10.215 (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. 0 (Ref.: By convention) 0 (Ref.: Internal calculation) 47.490 (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. 25.23 (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.
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.
23.68 5.19 0.00 (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.
Reaction properties

Au(element) + 0.75O2 + 3H+ ⇌ Au+3 + 1.5H2O

298.15 K, 1 bar log10K: -11.45 ΔH°r:-10259 J·mol-1 (Ref.: Internal calculation)
T(°C) 0 25 60 100 150 200 250 300
log10K -11.31 -11.45 -11.66 -11.92 -12.26 -12.62 -13.06 -13.60
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-624.416525 -0.098368 33850.496201 222.654169 -1971563.857251