Gallium (Ga) – Properties, Applications

Topics Covered

Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties


Gallium is a chemical element with Ga as its symbol. It belongs to group 13, periodic number 4 of the periodic table. Its atomic number is 31.

Gallium is a blue-gray metal with a orthorhombic crystalline structure. It is solid at normal room temperatures, but turns to liquid when slightly heated. Solid gallium can even be cut with a knife as it is so soft. It is stable in air and water; however dissolves in acids and alkalis.

Gallium is a byproduct during burning of coal, aluminum and zinc production. It also occurs in trace amounts in sphalerite, germanite, diaspore, and bauxite.

Chemical Properties

The chemical properties of gallium are provided in the table below.

Chemical Data
CAS number 7440-55-3
Thermal neutron cross section 2.8 barns/atom
Electrode potential -0.520 V
Ionic radius 0.620 Å
Electronegativity 1.81
X-ray absorption edge 1.195 Å
Electrochemical equivalent 2.45 g/A/h

Physical Properties

The following table discusses the physical properties of gallium.

Properties Metric Imperial
Density (@20°C/68°F) 5.1 g/cm3 0.184 lb/in3
Melting point 29.78°C 85.60°F
Boiling point 2204°C 3999°F

Mechanical Properties

The mechanical properties of gallium are tabulated below.

Properties Metric Imperial
Hardness, Vickers 50 50

Thermal Properties

The thermal properties of gallium are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@20-100°C/68-212°F) 58 µm/m°C 32.2 µin/in°F
Thermal conductivity 41 W/mK 285 BTU in/hr.ft².°F


The following are the application areas of gallium:

  • In mirrors
  • To form low-melting alloys
  • In high temperature thermometers
  • Bright, highly reflective surface coating for on glass
  • In LEDs for electronic display and watches
  • Semiconductor components


  1. SAMIR KORLA SAMIR KORLA United States says:

    this is really cool for my project, just put stuff like brittleness and malleability.

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