Gallium

Symbol: Ga
Atomic number: 31
Category: poor metals
Group: 13
Period: 4
Block: p
Atomic weight: 69.723 g/mol
Electrons per shell: 2, 8, 18, 3
CAS number: 7440-55-3
Phase: solid
Density: 5.91 kg/dm³ (near room temperature)
Melting point: 302.9146 K (29.7646 °C, 85.5763 °F)
Boiling point: 2477 K (2204 °C, 3999 °F)
Crystal structure: orthorhombic
Oxidation states: 3, 2, 1
Electronegativity: 1.81 (Pauling scale)
Name's origin: Gallia
Name's meaning: a Latin word meaning Gaul - modern France which was given after the home country of the element's discoverer
Facts:
- elemental gallium does not occur in nature, but as the Ga (III) salt, in trace amounts in bauxite and zinc ores
- liquefies slightly above room temperature, it will melt in the hand
- is not known to be essential in biology, but because of the biological handling of gallium's primary ionic salt Ga(III) as though it were iron(III), gallium ion localizes to and interacts with many processes in the body in which iron(III)
- while not considered toxic, the data about gallium are inconclusive: some sources suggest that it may cause dermatitis from prolonged exposure; other tests have not caused a positive reaction
- the only economic sources for gallium are as byproduct of aluminium and zinc production
- is used widely in LEDs and semiconductors