Los Alamos National Laboratory
Periodic Table of Elements: LANL

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Gallium metal is silver-white and melts at approximately body temperature (Wikipedia image). Gallium metal is silver-white and melts at approximately body temperature (Wikipedia image).


Atomic Number: 31 Atomic Radius: 187 pm (Van der Waals)
Atomic Symbol: Ga Melting Point: 29.76 °C
Atomic Weight: 69.72 Boiling Point: 2204 °C
Electron Configuration: [Ar]4s23d104p1 Oxidation States: 3


From the Latin word Gallia, France; also from Latin, gallus, a translation of "Lecoq," a cock. Predicted and described by Mendeleev as ekaaluminum, and discovered spectroscopically by Lecoq de Boisbaudran in 1875, who in the same year obtained the free metal by electrolysis of a solution of the hydroxide in KOH.


Gallium is often found as a trace element in diaspore, sphalerite, germanite, bauxite, and coal. Some flue dusts from burning coal have been shown to contain as much 1.5 percent gallium.




Ultra-pure gallium has a beautiful, silvery appearance, and the solid metal exhibits a conchoidal fracture similar to glass. The metal expands 3.1 percent on solidifying; therefore, it should not be stored in glass or metal containers, because they may break as the metal solidifies.

High-purity gallium is attacked only slowly by mineral acids.


Gallium wets glass or porcelain and forms a brilliant mirror when it is painted on glass. It is widely used in doping semiconductors and producing solid-state devices such as transistors.

Magnesium gallate containing divalent impurities, such as Mn+2, is finding use in commercial ultraviolet-activated powder phosphors. Gallium arsenide is capable of converting electricity directly into coherent light. Gallium readily alloys with most metals, and has been used as a component in low-melting alloys.


Its toxicity appears to be of a low order, but should be handled with care until more data is available.

