Gold

Gold • Transition Metal

Primary XPS region: Au4f
Overlapping regions: N/A
Binding energies of common chemical states:

Chemical state	Binding energy Au4f_7/2
Au metal	84.0 eV

Experimental information

N/A

Interpretation of XPS spectra

Au4f region has well-separated spin-orbit components (Δ=3.7eV).
- Peaks in the Au4f region have an asymmetric peak shape.
The Au4f_7/2 peak can be a useful binding energy reference (Au4f_7/2 at 84.00eV).
- Binding energy shifts may be observed with Au nanoparticles, however.
  - Casaletto et al. analyzed Au nanoparticles on different metal oxide supports with XPS[1] and found two states of gold, Au⁰ and Au¹⁺.
  - The Au¹⁺ state was shifted by 2eV from the Au⁰ state.

Reference

[1] Casaletto et al., Surf. Interface Anal. 2006; 38: 215–218.

About this element

Symbol: Au
Date of discovery: circa 3000 BC
Name origin: Old English geolo
Appearance: gold
Discoverer: unknown
Obtained from: earth crust, copper ores

Melting point: 1337.58 K
Boiling point: 3080 K
Density[kg/m³]: 19300
Molar volume: 10.21 × 10^-6 m³/mol
Protons/Electrons: 79
Neutrons: 118
Shell structure: 2,8,18,32,18,1
Electron configuration: [Xe]4f145d106s1
Oxidation state: 3,1
Crystal structure: cubic face centered

Gold, Latin aurium for "shining dawn", has been one of the most valued precious metals since prehistoric times and is mentioned several times in the Old Testament. Gold has been the standard for monetary exchange in many countries. While the metallic element takes on a yellow color en masse, when finely-divided it can also appear to be black, ruby, or purple in color. Being that gold is a soft metal, it is strengthened by being alloyed with other metals such as silver and copper. Gold’s heat and electrical conductivity qualities – as well as its resistance to heat, oxygen, moisture, and most corrosive agents – make it most applicable in coinage and jewelry. Seventy-five percent of all gold ever produced has been extracted since 1910. All gold ever refined would form a single cube twenty meters per side.