Galliums

Gallium is a chemical element with the symbol Ga and atomic number 31. It is a post-transition metal in group 13 of the periodic table. Gallium occurs only in trace amounts in minerals and is not found as a free element in nature. It was discovered in 1875 by French chemist Paul-Émile Lecoq de Boisbaudran through spectroscopic analysis of a sample from zinc ore and was named after Gaul (France).

Physically, gallium is a soft, silvery-blue metal that melts just above room temperature at 29.76 °C, so it can melt in a person's hand. It expands slightly when it solidifies, a property shared with few other metals. It is relatively resistant to oxidation in air and forms various compounds, including gallium oxide (Ga2O3), gallium(III) fluoride, and gallides such as gallium arsenide (GaAs) and gallium nitride (GaN). The most common stable isotopes are Ga-69 and Ga-71.

Occurrence and production: Gallium is primarily obtained as a byproduct of refining bauxite into alumina and from zinc ore processing. It is largely produced in small quantities due to its low abundance and specialized uses.

Applications: The dominant industrial use is in semiconductors. GaAs and GaN are essential in light-emitting diodes, laser diodes, and high-speed electronics; GaN-based devices are used in power electronics and fast transistors. Gallium oxide compounds are studied for wide-bandgap electronics. An alternative alloy, galinstan (gallium-indium-tin), is liquid at room temperature and used in low-friction seals and educational demonstrations.

Safety: Gallium and many gallium compounds are of low toxicity, but concern exists for compounds containing toxic elements such as arsenic (GaAs). Standard laboratory precautions apply; disposal should follow local regulations.