Gallium

Atomic Number 31; Atomic Weight 69,72; Density 5.904 g/ccm at 29.6 °C (solid),
6.095 g/ccm at 29.8 °C (liquid); Melting Point 29.78 °C; Valence +1,+2 or +3.

The name gallium comes from France (Latin “Gallia”) where it was found by Lecoq de Boisbaudran in 1875. Another explanation is the word “gallus”, the Latin counterpart of Lecoq (the cock).

Gallium is liquid at about room temperature and expands by approximately 3 % when solidifying.
Mendelejeff described gallium as “eka-aluminium”. It occurs as a trace element mainly in bauxite and is recovered as a by-product from the alumina production.

The principal fields of application are today III/V-semiconductors, especially gallium arsenide. Owing to its low melting point, high boiling point and low vapour pressure gallium is used for low melting point alloys and high temperature thermometers.