Gallium - Information

Atomic Number: 31

Atomic Weight: 69.723(1)

Electronic Configuration: [Ar]4s²3d¹⁰4p¹

Appearance - Ultra-pure gallium has a silvery appearance at 298K, and the solid metal exhibits a conchoidal fracture similar to glass.

History - Gallium was predicted and described by Mendeleev who named it ekaaluminum and later discovered by Lecoq de Boibaudran in 1875.

Origin - From Latin, gallus, a translation of "Lecoq", a cock).

Sources - Flue dusts from burning coal have been shown to contain as much 1.5 percent gallium. Diaspore, sphalerite, germanite, bauxite are also known to contain traces of gallium.

Uses -

• Gallium is one of the few metals that can be liquid at near-room temperatures. It also has a very long liquid range and a low vapour pressure at high temperatures. This leads to its use in high-temperature thermometers.
• Gallium easily alloys with most metals, and has been used as a component in low-melting alloys.
• Gallium 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.
• Commercial ultra violet-activated powder phosphors use magnesium gallate containing divalent impurities, such as Mn+2.
• Gallium arsenide can convert electricity directly into coherent light.

Handling and Costs - Little is known about the toxicity so care should obviously be taken. The metal will expand as it solidifies so it shouldn't be stored in glass or metal containers. Mineral acids will slowly attack gallium at a high level of purity. The metal is supplied in pure form at $3/g.