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Gallium

Source of the photo
http://gensonscience.wikispaces.com/Gallium
Author of the description
Gruiz Katalin

Atomic number

31

Atomic mass

69.72 g.mol -1

Electronegativity

1,8

Density

5.1 g.cm-3 at 20°C

Melting point

29.8 °C

Boiling point

2204 °C

Vanderwaals radius

0.161 nm

Ionic radius

0.083 nm (+3)

Isotopes

6

Electronic shell

[ Ar ] 3d10 4s24p1

Energy of first ionisation

578.6 kJ.mol -1

Energy of second ionisation

1978.8 kJ.mol -1

Energy of third ionisation

2389 kJ.mol -1

Energy of fourth ionisation

2962.3 kJ.mol -1

Standard potential

- 0.52 V

 

Solid gallium is a blue-gray metal with orthorhombic crystalline structure; very pure gallium has a stunning silvery color. Gallium is solid at normal room temperatures, but as well as mercury, cesium, and rubidium it becomes liquid when heated slightly. Solid gallium is soft enough to be cut with a knife. It is stable in air and water; but it reacts with and dissolves in acids and alkalis.

Applications

Liquid gallium wets porcelain and glass surfaces; it forms a bright, highly reflective surface when coated on glass. It can be used to create brilliant mirrors. Gallium easily alloys with most metals, so it is used to form low-melting alloys. The plutonium pits of nuclear weapons employ an alloy with gallium to stabilize the allotropes of plutonium.
Analog integrated circuits are the most common application for gallium, with optoelectronic devices (mostly laser diodes and light-emitting diodes) as the second largest end use. Gallium has semiconductor properties, especially as gallium arsendite (GaAs). This can convert electricity to light and is used in light emitting diodes (LEDs) for electronic display and watches.
Gallium is used in some high temperature thermometers.