Chemical element · reference page

79Au

Gold

Gold is element 79 (Au), located in period 6, group 11 and the d block. At room temperature its reference phase is solid. Its electron configuration is [Xe] 4f14 5d10 6s1.

Atomic number79

Standard atomic weight196.966570(4)

Group11

Period6

Blockd

Electron configuration[Xe] 4f14 5d10 6s1

Electronic structure

What controls its chemistry

The d subshell participates in the chemistry of gold. Transition metals can use electrons of similar energies in bonding, which is why variable oxidation states, coordination compounds and catalytic behaviour are common across the d block.

Its electron configuration, [Xe] 4f14 5d10 6s1, should be read together with the oxidation state of the compound: removing electrons changes which d orbitals are occupied and can alter colour, magnetism, bonding and reactivity.

Chemical forms

Compounds, ions and materials

For gold, important chemical forms include metals and alloys, oxides, halides and coordination compounds. Variable oxidation states are common because s and d electrons have similar energies, and ligands around the metal ion can strongly alter colour, magnetism and reactivity.

Physical behaviour

State and phase changes

The reference phase at room temperature is solid. The listed density is 19.3 g/cm³. The melting point is 1 337 K (1 064 °C). The boiling point is 3 243 K (2 970 °C). Pressure, purity and crystal structure can shift measured physical properties.

Occurrence and applications

Where gold is found and used

In practice, gold is encountered in jewellery, electronics and space technology.

In practice

Examples of real uses

Jewellery

Gold is used for colour, corrosion resistance, rarity, polish or mechanical properties in jewellery alloys.

Electronics

Gold is used in electronic components or materials where conductivity, semiconducting behaviour, optical response or chemical stability is useful.

Space technology

Gold is used in spacecraft electronics, coatings, radiation-resistant materials, propulsion or high-reliability alloys.

Periodic position

What its neighbours tell us

Gold is in period 6 and group 11. In the neighbourhood shown here, it lies between platinum and mercury in the same period; silver is above it and roentgenium below it in the same group. These positions make it possible to compare atomic size, ionisation energy and bonding behaviour with nearby elements.

Reference data

Physical and atomic properties

Classificationtransition metal

Phase at room temperatureSolid

Electron shells2 · 8 · 18 · 32 · 18 · 1

Density19.3 g/cm³

Melting point1 337 K (1 064 °C)

Boiling point3 243 K (2 970 °C)

Pauling electronegativity2.54

First ionisation energy890.1 kJ/mol

Electron affinity222.7 kJ/mol

Values describe the element or neutral atom where applicable. Physical data can depend on allotrope, pressure and measurement conditions.

History

Discovery and identification

Early use of gold is associated with the Middle East. That is not a single modern discovery event: early use, chemical identification and the later atomic-number definition belong to different stages.

Isotopes and atomic weight

How isotope composition changes the numbers

The standard atomic weight is 196.966570(4). This value refers to the isotopic composition of natural terrestrial material, not to the mass of one specific atom.

Gold has at least one stable isotope. Different isotopes have the same number of protons and therefore the same element identity, but different neutron numbers and atomic masses.

Safety

Handling and exposure

The hazards associated with gold depend on chemical form, dose and route of exposure. Pure gold, its ions and its compounds can have very different biological and environmental effects, so safety data should be checked for the actual substance being handled.