Gallium is a chemical element with the symbol Ga and atomic number 31. It is in group 13 of the periodic table, and thus has similarities to the other metals of the group, aluminium, indium, and thallium. Gallium does not occur as a free element in nature, but as gallium(III) compounds in trace amounts in zinc ores and in bauxite. Elemental gallium is a soft, silvery blue metal at standard temperature and pressure; however in its liquid state it becomes silvery white. If too much force is applied, the gallium may fracture conchoidally like glass. Gallium is found in alloys with many other metals. It forms eutectic mixtures with mercury (Hg) at −39 °C (−38 °F), and alloys with many post-transition metals except for zinc (Zn), cadmium (Cd), and mercury (Hg). Alloys containing gallium have low melting points (they melt just above room temperature) and are easily damaged by mechanical shock. Gallium easily alloys with most metals, and also alloys with metalloids such as arsenic (As) and semiconductors such as silicon (Si).
