About

Gallium is a soft, silvery metal famous for its low melting point of 29.76 °C (85.58 °F), which means it will melt in a person's hand. It also has one of the largest liquid ranges of any metal. It is a critical component in modern semiconductors, particularly for manufacturing gallium arsenide (GaAs) and gallium nitride (GaN) used in LEDs, cell phone amplifiers, and Blu-ray technology.

Atomic Properties

Atomic Number31

Atomic Weight69.723 u

Neutrons (common)38

Electron Configuration[Ar] 3d¹⁰ 4s² 4p¹

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p¹

Electrons per Shell2, 8, 18, 3

Electronegativity1.81

Electron Affinity29 kJ/mol

Oxidation States+3, +2, +1

Covalent Radius122 pm

Van der Waals Radius187 pm

Ionic Radius62 pm

Periodic Table Position

Group13

Period4

BlockP

Chemical SeriesPost-transition metals

Physical Properties

State at STPsolid

Appearancesilvery-white

Crystal Structureorthorhombic

Magnetic Orderingdiamagnetic

Speed of Sound2,740 m/s

Poisson Ratio0.25

Thermal Properties

Melting Point302.915 K

Boiling Point2,673 K

Triple Point302.915 K

Thermal Expansion0 1/K

Thermal Conductivity40.6 W/(m·K)

Specific Heat0.371 J/(g·K)

Molar Heat25.86 J/(mol·K)

Heat of Fusion5.59 kJ/mol

Heat of Vaporization256 kJ/mol

Abundance

In Earth's Crust19 ppm

In Ocean0 ppm

In Solar System0.04 ppm

In Universe0.01 ppm

Discovery

Discovered byLecoq de Boisbaudran

Discovery Year1,875

Occurrenceprimordial

CAS Number7440-55-3

Electron Configuration

Energy

↿⇂

↿

Isotopes of Gallium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁶⁶Ga	65.931589	—	9.304 h	Positron Emission, Electron Capture
⁶⁷Ga	66.928202	—	3.2617 d	Electron Capture
⁶⁸Ga	67.927980	—	67.842 m	Positron Emission, Electron Capture
⁶⁹Ga	68.925570	60.108%	Stable	Stable
⁷¹Ga	70.924700	39.892%	Stable	Stable
⁷²Ga	71.926366	—	14.025 h	Beta Minus Decay

Interactive Visualization

Explore the 3D Bohr model of Gallium in our interactive viewer.

View 3D Model of Gallium