Electron configuration and elemental properties of gallium.
Electron configuration and elemental properties of gallium.
Credit: Greg Robson/Creative Commons, Andrei Marincas Shutterstock
Atomic Number: 31
Atomic Symbol: Ga
Atomic Weight: 69.723
Melting Point: 85.57 F (29.76 C)
Boiling Point: 3,999.2 F (2,204 C)

Word origin: Gallium comes from Gallia, the Latin name for France. It also has origins in the Latin word gallus, a translation of Lecoq, the term for a rooster, and also the first name of the scientist who discovered the element.

Discovery: Chemist Lecoq de Boisbaudran discovered the element spectroscopically in 1875. He was also able to obtain the free metal by electrolysis of a solution of potassium hydroxide (KOH). Dmitri Mendeleev, the Russian chemist who created the first version of the Periodic Table of the Elements, predicted and described the metal as ekaaluminum.

Properties of gallium

Gallium is classified as a post-transition metal. In its pure, solid form, gallium is silvery white and has a fracture pattern similar to glass. It is one of four metals — besides mercury, cesium and rubidium — that can be liquid near room temperature. The liquid form should not be kept in glass or metal containers because when turning to a solid state, gallium expands about 3.1 percent. This process could break the container.

Crystals of 99.999 percent gallium, grown in a lab
Crystals of 99.999 percent gallium, grown in a lab
Credit: foobar/Creative Commons

Gallium has two stable isotopes: Ga-69 and Ga-71.

Sources of gallium

Gallium is a byproduct of the manufacture of aluminum. It is also found as a trace element in the minerals diaspore, sphalerite, germanite, bauxite and coal.

Uses of gallium

Gallium can form a very lustrous mirror when painted on glass. It is also used to wet glass and ceramics. Gallium, like other liquid metals, can be used to make thermostats, switches, barometers, heat transfer systems, as well as thermal cooling and heating devices.

Gallium easily bonds with most metals and is often added to low-melting alloys. Gallium nitride and gallium arsenide are important materials for making semiconductors and light-emitting diodes (LEDs).

A gallium scan is a nuclear medicine test that uses the radioactive isotope, Gallium-67, to look for inflammation, infection or cancer in the body.

(Source: Los Alamos National Laboratory)