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.
See also: 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.
