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It's Elemental

The Element Krypton

[Click for Isotope Data]


36 Kr Krypton 83.798

Atomic Number: 36

Atomic Weight: 83.798

Melting Point: 115.79 K (-157.36°C or -251.25°F)

Boiling Point: 119.93 K (-153.22°C or -243.80°F)

Density: 0.003733 grams per cubic centimeter

Phase at Room Temperature: Gas

Element Classification: Non-metal

Period Number: 4

Group Number: 18

Group Name: Noble Gas

What's in a name? From the Greek word for hidden, kryptos.

Say what? Krypton is pronounced as KRIP-ton.

History and Uses:

Krypton was discovered on May 30, 1898 by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist, while studying liquefied air. Small amounts of liquid krypton remained behind after the more volatile components of liquid air had boiled away. The earth's atmosphere is about 0.0001% krypton.

The high cost of obtaining krypton from the air has limited its practical applications. Krypton is used in some types of photographic flashes used in high speed photography. Some fluorescent light bulbs are filled with a mixture of krypton and argon gases. Krypton gas is also combined with other gases to make luminous signs that glow with a greenish-yellow light. In 1960, the length of the meter was defined in terms of the orange-red spectral line of krypton-86, an isotope of krypton.

Once thought to be completely inert, krypton is known to form a few compounds. Krypton difluoride (KrF2) is the easiest krypton compound to make and gram amounts of it have been produced.

For those that are curious, pictures of krypton gas and krypton plasma can be found in the Questions and Answers section of this site.

Estimated Crustal Abundance: 1×10-4 milligrams per kilogram

Estimated Oceanic Abundance: 2.1×10-4 milligrams per liter

Number of Stable Isotopes: 5 (View all isotope data)

Ionization Energy: 14.000 eV

Oxidation States: 0

Electron Shell Configuration:


2s2   2p6

3s2   3p6   3d10

4s2   4p6

Citation and linking information

For questions about this page, please contact Steve Gagnon.