A silver-white, malleable and ductile metal, symbol Al. → Atomic number 13; → atomic weight 26.98154; → melting point 660.37°C; → boiling point 2,467°C; → specific gravity 2.6989 at 20°C. Its electric → conductivity is comparable with that of copper, so that being much lighter it is used extensively for transmission lines. The metal and its → alloys have strength with lightness. The → reflectivity of aluminium is high and it is therefore used broadly for coating → mirrors (→ aluminization). Aluminium occurs widely in clays; it is extracted mainly from bauxite. It has several → radioactive isotopes with half-lives from 2.3 sec (23Al) to 6.56 min (29Al). When aluminium is bombarded with → alpha particles, its atoms first turn into radioactive → phosphorus, then into → silicon. This occurs naturally in → massive stars.
The name of the chemical element, was coined by Sir Humphry Davy (1778-1829), from L. alumen "alum; bitter salt," akin to Gk. aludoimos "bitter" and Eng. ale. Davy originally called it alumium (1808), then modified this to aluminum, which remains the U.S. word, but British editors in 1812 further amended it to aluminium. In 1825, the Danish physicist Hans Christian Oersted (1777-1851) isolated impure aluminium. The pure metal was first isolated by the German chemist Friedrich Wöhler (1800-1882) in 1827.