Background | Name | Sources | Uses | Substitutes and Alternative Sources
Background Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named Mendeleev who said that gallium would be very much like aluminum in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)3 in potassium hydroxide (KOH).
Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of temperatures than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).
Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be toxic.