Gallium

General:

Name:Gallium Symbol:Ga
Type: Metal Atomic weight:69.723
Density @ 293 K:5.907 g/cm3 Atomic volume:11.8 cm3/mol
Discovered:

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.

States

State (s, l, g):solid
Melting point:302.91 K (29.76 °C) Boiling point:2673 K (2200 °C)

Energies

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

Oxidation & Electrons

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

Appearance & Characteristics

Structure:orthorhombic Color:silvery-blue
Hardness:1.5 mohs
Harmful effects:

Gallium is considered to be non-toxic.

Characteristics:

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.

The solid metal fractures conchoidally. (Conchoidally means like a shell - the fractured surfaces are curved like a sea shell.)

Gallium has the largest liquid range of any element and is one of the few metals that is liquid near room temperature (m.pt. 29.76 °C, 85.6 °F ), melting in the hand.

The other metals with this property are cesium, francium and mercury. 

Bromine is the only non-metallic element that is liquid at or around room-temperature.

Gallium liquid clings to or wets glass and similar surfaces.

Gallium also has the unusual property that (like water) it expands as it freezes.

Four other elements expand when they freeze; silicon, bismuth, antimony and germanium


Uses:

Low melting gallium alloys are used in some medical thermometers as non-toxic substitutes for mercury.

Gallium arsenide is used in semiconductor production mainly for laser diodes, light-emitting diodes and solar panels. It is also used to create brilliant mirrors.

Reactions

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-

Compounds

Oxide(s):Ga2O3 Chloride(s):GaCl, Ga2Cl6
Hydride(s):GaH3

Radius

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

Conductivity

Thermal conductivity:40.6 W m-1 K-1 Electrical conductivity:1.8 x 106 S m-1

Abundance & Isotopes

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
Source:

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.

Isotopes:

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.

Other

Other:

 

Related Products