Barium

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

Atomic number

56

Atomic mass

137.33 g.mol -1

Electronegativity

0.9

Density

3.5 g.cm-3 at 20°C

Melting point

725 °C

Boiling point

1640 °C

Vanderwaals radius

0.222 nm

Ionic radius

0.135

Isotopes

16

Electronic shell

[ Xe ] 6s2

Energy of first ionisation

502.7 kJ.mol -1

Energy of second ionisation

965 kJ.mol -1

Standard potential

- 2.90 V

Discovered by

Sir Humphrey Davy in 1808

 

Barium is a silvery-white metal that can be found in the environment, where it exists naturally. It occurs combined with other chemicals, such as sulfur, carbon or oxygen. Ii is very light and its density is half that of iron. Barium oxidizes in air, reacts vigoroulsy with water to form the hydroxide, liberating hydrogen. Barium reacts with almost all the non-metals, forming often poisouning compounds.

 

Applications

Barium is often used in barium-nickel alloys for spark-plug electrodes an in vacuum tubes as drying and oxygen-removing agent. It is also used in fluorescent lamps: impure barium sulfide phosphoresces after exposure to the light.
Barium compounds are used by the oil and gas industries to make drilling mud. Drilling mud simplifies drilling through rocks by lubricating the drill.
Barium compounds are also used to make paint, bricks, tiles, glass, and rubber. Barium nitrate and clorate give fireworks a green colour.