gallium science definition

A rare, silvery metallic element that is found as a trace element in coal, in bauxite, and in several minerals. It is liquid near room temperature and expands when it solidifies. It is used in thermometers and semiconductors. Atomic number 31; atomic weight 69.72; melting point 29.78°C; boiling point 2,403°C; specific gravity 5.907; valence 2, 3. See Periodic Table.