What is KRYPTON?
Krypton is a chemical element with symbol Kr and atomic number 36. It is a member of group 18 elements. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. With rare exceptions, krypton is chemically inert.
Having discovered the noble gas argon, extracted from air, William Ramsay and Morris William Travers of University College, London, were convinced this must be one of a new group of elements of the periodic table. They decided others were likely to be hidden in the argon and by a process of liquefaction and evaporation they hoped it might leave behind a heavier component, and it did. It yielded krypton in the afternoon of 30th May 1898, and they were able to isolate about 25 cm3 of the new gas. This they immediately tested in a spectrometer, and saw from its atomic spectrum that it was a new element.
It’s not just Superman’s home planet; Krypton is one of the rarest gases on Earth, composing only 1 part per million of the atmosphere by volume.
This noble gas is colorless and odorless. It has a full outer shell of electrons, rendering it largely inert to reactions with other elements. Unlike its fellow noble gas neon, however, krypton does make some compounds. The most common is the colorless solid krypton difluoride (KrF2), according to the Thomas Jefferson National Linear Accelerator Laboratory. Krypton difluoride is only stable below minus 22 degrees Fahrenheit (minus 30 degrees Celsius), according to Chemicool.
Because krypton is so rare (and thus expensive), it has limited use. The gas is injected into some incandescent lightbulbs, because it extends the life of the tungsten filament that makes those bulbs glow, according to Universal Industrial Gases Inc., a supplier of industrial gases production equipment and related services. Because it is such a heavy gas, krypton is also sealed between the glass of some double-paned windows to help them trap heat. But even for this purpose, the noble gas argon is usually used because it is cheaper, according to Universal Industrial Gases.
Just the facts
- Atomic number (number of protons in the nucleus): 36
- Atomic symbol (on the Periodic Table of Elements): Kr
- Atomic weight (average mass of the atom): 83.798
- Density: 0.003733 grams per cubic centimeter
- Phase at room temperature: Gas
- Melting point: minus 251.25 F (minus 157.36 C)
- Boiling point: minus 243.80 F (minus 153.22 C)
- Number of isotopes (atoms of the same element with a different number of neutrons): 37
- Most common isotopes: Kr-84 (56.98 percent of natural abundance), Kr-86 (17.279 percent of natural abundance), Kr-82 (11.59 percent of natural abundance), Kr-83 (11.5 percent of natural abundance), Kr-80 (2.28 percent of natural abundance) and Kr-78 (0.35 percent of natural abundance)
Image explanationThere are many different isotopes of krypton. This symbol represents the isotope krypton-86.
AppearanceKrypton is a gas with no colour or smell. It does not react with anything except fluorine gas.
UsesKrypton is used commercially as a filling gas for energy-saving fluorescent lights. It is also used in some flash lamps used for high-speed photography.
Unlike the lighter gases in its group, it is reactive enough to form some chemical compounds. For example, krypton will react with fluorine to form krypton fluoride. Krypton fluoride is used in some lasers.
Radioactive krypton was used during the Cold War to estimate Soviet nuclear production. The gas is a product of all nuclear reactors, so the Russian share was found by subtracting the amount that came from Western reactors from the total in the air.
From 1960 to 1983 the isotope krypton-86 was used to define the standard measure of length. One metre was defined as exactly 1,650,763.73 wavelengths of a line in the atomic spectrum of the isotope
.Biological roleKrypton has no known biological role.
Natural abundanceKrypton is one of the rarest gases in the Earth’s atmosphere. It makes up just 1 part per million by volume. It is extracted by distillation of air that has been cooled until it is a liquid.
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