|Type: Metal||Atomic weight:69.723|
|Density @ 293 K:5.907 g/cm3||Atomic volume:11.8 cm3/mol|
Gallium was discovered by Paul E. Lecoq de Boisbaudran through a spectroscope in 1875. Its now characteristic spectrum (two violet lines) identified it as a new element. De Boisbaudran later isolated gallium by electrolysis of its hydroxide in potassium hydroxide solution. The origin of the name comes from the Latin word 'Gallia', meaning France.
|State (s, l, g):solid|
|Melting point:302.91 K (29.76 °C)||Boiling point:2673 K (2200 °C)|
|Specific heat capacity:0.37 J g-1 K-1||Heat of atomization:277 kJ mol-1|
|Heat of fusion:5.590 kJ mol-1||Heat of vaporization :258.70 kJ mol-1|
|1st ionization energy:578.8 kJ mol-1||2nd ionization energy:1979.3 kJ mol-1|
|3rd ionization energy:2963 kJ mol-1||Electron affinity:41 kJ mol-1|
|Shells:2,8,18,3||Electron configuration:[Ar] 3d10 4s2 4p1|
|Minimum oxidation number:0||Maximum oxidation number:3|
|Min. common oxidation no.:0||Max. common oxidation no.:3|
|Electronegativity (Pauling Scale):1.81||Polarizability volume:8.1 Å3|
Gallium is considered to be non-toxic.
Gallium is a silvery, glass-like, soft metal. It sits close to the non-metals in the periodic table and its metallic properties aren't as obviously metallic as most other metals. Solid gallium is brittle and is a poorer electrical conductor than lead.
Low melting gallium alloys are used in some medical thermometers as non-toxic substitutes for mercury.
|Reaction with air:mild, ⇒ Ga2O3||Reaction with 6 M HCl:mild, ⇒ H2, GaCl3|
|Reaction with 15 M HNO3:||Reaction with 6 M NaOH: mild,⇒ H2, [Ga(OH4)]2-|
|Atomic radius:135 pm||Ionic radius (1+ ion):pm|
|Ionic radius (2+ ion):pm||Ionic radius (3+ ion): 76 pm|
|Ionic radius (2- ion):pm||Ionic radius (1- ion):pm|
|Thermal conductivity:40.6 W m-1 K-1||Electrical conductivity:1.8 x 106 S m-1|
|Abundance earth's crust:19 parts per million by weight, 5.5 parts per million by moles|
|Abundance solar system:40 parts per billion by weight, 0.6 parts per billion by moles|
|Cost, pure:$220 per 100g|
|Cost, bulk:$ per 100g|
Gallium does not exist free in nature and there are no minerals with any substantial gallium content. Commercially, most gallium is extracted as a byproduct of aluminum and zinc production. Gallium is also extracted from the flue dusts of coal.
Gallium has 24 isotopes whose half-lives are known, with mass numbers 61 to 84. Of these, two are stable: 69Ga and 71Ga with natural abundances of 60.1% and 39.9% respectively.