Gallium

Gallium (chemical symbol: Ga) is a chemical element with atomic number 31. It is a soft metal with a silvery-white appearance. It belongs to group 13 of the periodic table (the boron group), and shares properties with aluminium and indium.

The most notable property of gallium is that its melting point is below room temperature: approximately 30 degrees Celsius. This means that solid gallium can melt in the palm of the hand. Its boiling point, however, is very high, making it useful for high-temperature applications.

Physical and chemical properties

Gallium does not occur naturally in pure form in the earth; it is typically found in compounds or in small quantities within other ores. When it freezes, it exhibits a distinctive property: like water, its solid form occupies more volume than its liquid form, and therefore a container into which it is poured can crack. It also reacts with other metals, particularly aluminium, attacking it corrosively.

Extraction and production

Gallium is typically obtained as a by-product of the bauxite process (aluminium ore refining) and zinc refining. There is no major ore worked specifically for gallium; consequently, the amount recovered depends on the output of aluminium and zinc refineries.

Applications

The primary use of gallium lies in electronic devices, particularly in compounds such as gallium arsenide and gallium nitride. These are used in LED lights, lasers, and high-frequency components in modern mobile phones. It is also used in solar cells and integrated circuits.