Gold is a chemical element with the symbol Au (from Latin aurum 'gold') and atomic number 79. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal in pure form. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions.

Gold often occurs in free elemental (native state), as nuggets or grains, in rocks, veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides).

Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid), forming a soluble tetrachloroaurate anion. Gold is insoluble in nitric acid alone, which dissolves silver and base metals, a property long used to refine gold and confirm the presence of gold in metallic substances, giving rise to the term 'acid test'. Gold dissolves in alkaline solutions of cyanide, which are used in mining and electroplating. Gold also dissolves in mercury, forming amalgam alloys, and as the gold acts simply as a solute, this is not a chemical reaction.

A relatively rare element, gold is a precious metal that has been used for coinage, jewelry, and other arts throughout recorded history. In the past, a gold standard was often implemented as a monetary policy. Gold coins ceased to be minted as a circulating currency in the 1930s, and the world gold standard was abandoned for a fiat currency system after the Nixon shock measures of 1971.

In 2020, the world's largest gold producer was China, followed by Russia and Australia. A total of around 201,296 tonnes of gold exists above ground, as of 2020. This is equal to a cube with each side measuring roughly 21. 7 meters (71 ft). The world's consumption of new gold produced is about 50% in jewelry, 40% in investments, and 10% in industry. Gold's high malleability, ductility, resistance to corrosion and most other chemical reactions, and conductivity of electricity have led to its continued use in corrosion-resistant electrical connectors in all types of computerized devices (its chief industrial use). Gold is also used in infrared shielding, the production of colored glass, gold leafing, and tooth restoration. Certain gold salts are still used as anti-inflammatories in medicine.

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Atomic properties

Standard atomic weight196.966 ±4·10-6
Atomic mass196.966 u

Atomic radii

Radius (empirical)144 pm
Radius (calculated)174 pm
Covalent radius136 ±6 pm
Van der Waals radius166 pm

Atomic shell

Electron configurationXe 4f14 5d10 6s1
Ionization energy(1st) 9.225554 eV
(2nd) 20.203 eV
(3rd) 30 eV
(4th) 45 eV
(5th) 60 eV
Shell model

Physical properties

Density19.32 g·cm−3 (293.1 K)
Molar volume1.021·10-5 m3·mol−1
Speed of sound2,030 m·s−1


Melting point1,337 K
Boiling point3,243 K
Liquid range1,905 K


Melting enthalpy12.5 kJ·mol-1
Enthalpy of vaporization330 kJ·mol-1
Binding energy368 kJ·mol-1

Heat and conductivity

Specific heat capacity128 J·kg−1·K−1
Thermal conductivity320 W·m-1·K-1
Expansion coefficient1.42·10-5 K-1
Work function5.1 eV


Mohs hardness2.53
Brinell hardness2,450 NM·m-2
Vickers hardness216 NM·m-2

Elastic properties

Young’s modulus78 GPa
Shear modulus27 GPa
Bulk modulus220 GPa
Poisson’s ratio0.44

Electrical properties

Electrical conductivity4.55·107 S·m-1
Resistance2.199·10-8 Ωm


Magnetic susceptibility-2.801·10-5 cm3·mol−1 (296 K)

Optical properties

Reflectivity95 %

Chemical properties

Oxidation state-1, 0, +1, +2, +3, +5
Standard potential1.52 V (Au3+ + 3e- → Au)


Pauling scale2.54
Allred-Rochow scale1.42
Mulliken scale1.87
Nagle scale1.53
Pearson absolute negativity5.77 eV

Other properties

Natural occurrenceprimordial
Crystal structureFace-centered cubic
Goldschmidt Classificationsiderophile
Superconductorwithout transition tempperature
Price/kg44,800 USD

Natural abundances

0.6 ppb ≈ 6.03·109 M☉
1 ppb ≈ 1.98·109 Mt
170 ppb ≈ 170 mg
Earth’s crust
3.1 ppb ≈ 85.8 Mt
0.05 ppb ≈ 68.5 kt
Flowing water
0.002 ppb ≈ 32 t
Human body
100 ppb ≈ 7 mg