Krypton
Krypton | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Pronunciation | /ˈkrɪptɒn/ | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Appearance | colorless gas, exhibiting a whitish glow in an electric field | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Standard atomic weight Ar°(Kr) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Krypton in the periodic table | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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kJ/mol | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Heat of vaporization | 9.08 kJ/mol | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Molar heat capacity | 20.95[6] J/(mol·K) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Vapor pressure
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Atomic properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Discovery and first isolation | William Ramsay and Morris Travers (1898) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Isotopes of krypton | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Krypton (from
Krypton, like the other noble gases, is used in lighting and
History
Krypton was discovered in Britain in 1898 by William Ramsay, a Scottish chemist, and Morris Travers, an English chemist, in residue left from evaporating nearly all components of liquid air. Neon was discovered by a similar procedure by the same workers just a few weeks later.[12] William Ramsay was awarded the 1904 Nobel Prize in Chemistry for discovery of a series of noble gases, including krypton.[13]
In 1960, the
Characteristics
Krypton is characterized by several sharp emission lines (
Isotopes
Naturally occurring krypton in Earth's atmosphere is composed of five
Chemistry
Like the other noble gases, krypton is chemically highly unreactive. The rather restricted chemistry of krypton in the +2 oxidation state parallels that of the neighboring element
Following the first successful synthesis of xenon compounds in 1962, synthesis of krypton difluoride (KrF
2) was reported in 1963. In the same year, KrF
4 was reported by Grosse, et al.,[28] but was subsequently shown to be a mistaken identification.[29] Under extreme conditions, krypton reacts with fluorine to form KrF2 according to the following equation:
Krypton gas in a
The complex can undergo spontaneous or stimulated emission, reducing its energy state to a metastable, but highly repulsive ground state. The ground state complex quickly dissociates into unbound atoms:
The result is an exciplex laser which radiates energy at 248 nm, near the ultraviolet portion of the spectrum, corresponding with the energy difference between the ground state and the excited state of the complex.[31]
Compounds with krypton bonded to atoms other than
The reaction of KrF
2 with B(OTeF
5)
3 produces an unstable compound, Kr(OTeF
5)
2, that contains a krypton-
, produced by the reaction of KrF
2 with [HC≡NH]+
[AsF−
6] below −50 °C.[35][36] HKrCN and HKrC≡CH (krypton hydride-cyanide and hydrokryptoacetylene) were reported to be stable up to 40 K.[27]
Krypton hydride (Kr(H2)4) crystals can be grown at pressures above 5 GPa. They have a face-centered cubic structure where krypton octahedra are surrounded by randomly oriented hydrogen molecules.[32]
Natural occurrence
Earth has retained all of the noble gases that were present at its formation except
Applications
Krypton's multiple emission lines make ionized krypton gas discharges appear whitish, which in turn makes krypton-based bulbs useful in photography as a white light source. Krypton is used in some photographic flashes for high speed photography. Krypton gas is also combined with mercury to make luminous signs that glow with a bright greenish-blue light.[39]
Krypton is mixed with argon in energy efficient fluorescent lamps, reducing the power consumption, but also reducing the light output and raising the cost.[40] Krypton costs about 100 times as much as argon. Krypton (along with xenon) is also used to fill incandescent lamps to reduce filament evaporation and allow higher operating temperatures.[41]
Krypton's white discharge is sometimes used as an artistic effect in gas discharge "neon" tubes. Krypton produces much higher light power than neon in the red spectral line region, and for this reason, red lasers for high-power laser light-shows are often krypton lasers with mirrors that select the red spectral line for laser amplification and emission, rather than the more familiar helium-neon variety, which could not achieve the same multi-watt outputs.[42]
The krypton fluoride laser is important in nuclear fusion energy research in confinement experiments. The laser has high beam uniformity, short wavelength, and the spot size can be varied to track an imploding pellet.[43]
In experimental
Krypton-83 has application in magnetic resonance imaging (MRI) for imaging airways. In particular, it enables the radiologist to distinguish between hydrophobic and hydrophilic surfaces containing an airway.[44]
Although xenon has potential for use in
Krypton is used occasionally as an insulating gas between window panes.[50] SpaceX Starlink uses krypton as a propellant for their electric propulsion system.[51]
Precautions
Krypton is considered to be a non-toxic
References
- ^ "Standard Atomic Weights: Krypton". CIAAW. 2001.
- ISSN 1365-3075.
- ^ Krypton. encyclopedia.airliquide.com
- ^ "Section 4, Properties of the Elements and Inorganic Compounds; Melting, boiling, triple, and critical temperatures of the elements". CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. 2005.
- ^ ISBN 1-4398-5511-0.
- ^ Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases". Kirk Othmer Encyclopedia of Chemical Technology. Wiley. pp. 343–383. doi:10.1002/0471238961.0701190508230114.a01.
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- ^ a b Patrignani, C.; et al. (. See p. 768
- .
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- ^ "The BIPM and the evolution of the definition of the metre". Bureau International des Poids et Mesures. 2014-07-26. Retrieved 2016-06-23.
- ^ Penzes, William B. (2009-01-08). "Time Line for the Definition of the Meter". National Institute of Standards and Technology. Archived from the original on 2016-08-12. Retrieved 2016-06-23.
- S2CID 121450003.
- ISBN 978-0-87389-535-4.
- ^ Gibbs, Philip (1997). "How is the speed of light measured?". Department of Mathematics, University of California. Archived from the original on 2015-08-21. Retrieved 2007-03-19.
- ^ Unit of length (meter), NIST
- ^ "Spectra of Gas Discharges". Archived from the original on 2011-04-02. Retrieved 2009-10-04.
- ^ "Krypton" (PDF). Argonne National Laboratory, EVS. 2005. Archived from the original (PDF) on 2009-09-29. Retrieved 2007-03-17.
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- .
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- ^ Thonnard, Norbert; MeKay, Larry D.; Labotka, Theodore C. (2001-02-05). "Development of Laser-Based Resonance Ionization Techniques for 81-Kr and 85-Kr Measurements in the Geosciences" (PDF). University of Tennessee, Institute for Rare Isotope Measurements. pp. 4–7. Retrieved 2007-03-20.
- ^ "Resources on Isotopes". U.S. Geological Survey. Archived from the original on 2001-09-24. Retrieved 2007-03-20.
- ^ a b Bartlett, Neil (2003). "The Noble Gases". Chemical & Engineering News. Retrieved 2006-07-02.
- PMID 17812982.
- S2CID 189775335.
- ISSN 0021-8979.
- PMID 9912935.
- ^ .
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- ^ "Periodic Table of the Elements" (PDF). Los Alamos National Laboratory's Chemistry Division. pp. 100–101. Archived from the original (PDF) on November 25, 2006. Retrieved 2007-04-05.
- ISBN 978-0-12-023646-6.
- ISBN 978-1-4020-6972-7.
- ^ "How Products are Made: Krypton". Retrieved 2006-07-02.
- doi:10.1086/310513.
- ^ "Mercury in Lighting" (PDF). Cape Cod Cooperative Extension. Archived from the original (PDF) on 2007-09-29. Retrieved 2007-03-20.
- ^ Lighting: Full-Size Fluorescent Lamps. McGraw-Hill Companies, Inc. (2002)
- ^ Properties, Applications and Uses of the "Rare Gases" Neon, Krypton and Xenon. Uigi.com. Retrieved on 2015-11-30.
- ^ "Laser Devices, Laser Shows and Effect" (PDF). Archived from the original (PDF) on 2007-02-21. Retrieved 2007-04-05.
- ^ Sethian, J.; M. Friedman; M. Myers. "Krypton Fluoride Laser Development for Inertial Fusion Energy" (PDF). Plasma Physics Division, Naval Research Laboratory. pp. 1–8. Archived from the original (PDF) on 2011-09-29. Retrieved 2007-03-20.
- PMID 16344474.
- PMID 17122371.
- PMID 19562336.
- ^ Sanger, David E.; Shanker, Thom (2003-07-20). "N. Korea may be hiding new nuclear site". Oakland Tribune. Archived from the original on 2016-04-09. Retrieved 2015-05-01.
- ^ Bradley, Ed; Martin, David (2000-03-16). "U.S. Intelligence Find Evidence of Pakistan Producing Nuclear Weapons, CBS". CBS Evening News with Dan Rather. Archived from the original on 2016-10-18. Retrieved 2015-05-01.
- ISSN 0160-4120.
- cleantechnica.com. Retrieved 17 May 2018.
- ^ SpaceX. "Starlink Mission". YouTube. Event occurs at 7:10. Archived from the original on 2021-11-03.
- ^ Properties of Krypton Archived 2009-02-19 at the Wayback Machine. Pt.chemicalstore.com. Retrieved on 2015-11-30.
- S2CID 29886337.
Further reading
- William P. Kirk "Krypton 85: a Review of the Literature and an Analysis of Radiation Hazards", Environmental Protection Agency, Office of Research and Monitoring, Washington (1972)
External links
- Krypton at The Periodic Table of Videos(University of Nottingham)
- Krypton Fluoride Lasers, Plasma Physics Division Naval Research Laboratory