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Krypton [Kr]
CAS-ID: 7439-90-9
An: 36 N: 48
Am: 83.798 g/mol
Group No: 18
Group Name: Noble Gases
Block: p-block  Period: 4
State: Gas
Colour: Colourless Classification: Non-metallic
Boiling Point: 119.93K (-153.22°C)
Melting Point: 115.79K (-157.36°C)
Critical temperature: 209.4K (-63.7°C)
Density: 3.749g/l
Availability: Krypton is present in the air at about 1 ppm.
Discovery Information
Who: Sir William Ramsey, M.W. Travers
When: 1898
Where: Great Britain
Name Origin
Greek: kryptos (hidden).
 "Krypton" in different languages.
Sources
Forms around 1 millionth of the atmosphere. It is obtained from production of liquid air.
It is one of the products of uranium fission.
Abundance
 Universe: 0.04 ppm (by weight)
 Atmosphere: 1.14 ppm
 Earth's Crust: 1 x 10-5 ppm
 Seawater: 2.1 x 10-4 ppm
Uses
Used in fluorescent bulbs, flashbulbs, and as a wavelength standard.
One major use of krypton is the krypton fluorine laser. Certain amounts of energy are added to force krypton gas to react with fluorine gas to become KrF excited state complex.
The compound will decompose once the energy supply stops. During the decomposition process, the excess energy stored in the excited state complex will be emitted in the form of strong ultraviolet laser radiation.
History
Krypton was discovered in Great Britain in 1898 by Sir William Ramsay and Morris Travers in residue left from evaporating nearly all components of liquid air.
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