Xenon

For other uses, see Xenon (disambiguation).

54 iodine ← xenon → caesium Kr ↑ Xe ↓ Rn Periodic table - Extended periodic table
General
Name, symbol, number	xenon, Xe, 54
Chemical series	noble gases
Group, period, block	18, 5, p
Appearance	colorless gas
Standard atomic weight	131.293(6) g·mol−1
Electron configuration	[Kr] 4d10 5s2 5p6
Electrons per shell	2, 8, 18, 18, 8
Physical properties
Phase	gas
Density	(0 °C, 101.325 kPa) 5.894 g/L
Melting point	(101.325 kPa) 161.4 K (−111.7 °C, −169.1 °F)
Boiling point	(101.325 kPa) 165.03 K (−108.12 °C, −162.62 °F)
Triple point	161.405 K (-112°C), 81.6 (2005) "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 edition, Boca Raton, Florida: CRC Press.  kPa
Critical point	289.77 K, 5.841 MPa
Heat of fusion	(101.325 kPa) 2.27 kJ·mol−1
Heat of vaporization	(101.325 kPa) 12.64 kJ·mol−1
Heat capacity	(100 kPa, 25 °C) 20.786 J·mol−1·K−1
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k at T/K 83 92 103 117 137 165
Atomic properties
Crystal structure	cubic face centered
Oxidation states	0, +1, +2, +4, +6, +8 (rarely more than 0) (weakly acidic oxide)
Electronegativity	2.6 (Pauling scale)
Ionization energies	1st: 1170.4 kJ·mol−1
	2nd: 2046.4 kJ·mol−1
	3rd: 3099.4 kJ·mol−1
Atomic radius (calc.)	108 pm
Covalent radius	130 pm
Van der Waals radius	216 pm
Miscellaneous
Magnetic ordering	nonmagnetic
Thermal conductivity	(300 K) 5.65x10-3  W·m−1·K−1
Speed of sound	(liquid) 1090 m/s
CAS registry number	7440-63-3
Selected isotopes
Main article: Isotopes of xenon iso NA half-life DM DE (MeV) DP 124Xe 0.095% 124Xe is stable with 70 neutrons 125Xe syn 16.9 h ε 1.652 125I 126Xe 0.089% 126Xe is stable with 72 neutrons 127Xe syn 36.345 d ε 0.662 127I 128Xe 1.91% 128Xe is stable with 74 neutrons 129Xe 26.4% 129Xe is stable with 75 neutrons 130Xe 4.07% 130Xe is stable with 76 neutrons 131Xe 21.2% 131Xe is stable with 77 neutrons 132Xe 26.9% 132Xe is stable with 78 neutrons 133Xe syn 5.247 d β− 0.427 133Cs 134Xe 10.4% 134Xe is stable with 80 neutrons 135Xe syn 9.14 h β− 1.16 135Cs 136Xe 8.86% 136Xe is stable with 82 neutrons
References
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Xenon (pronounced /ˈzɛnɒn/Xenon, entry in the Oxford English Dictionary, prepared by J. A. Simpson and E. S. C. Weiner, vol. 20, second edition, Oxford: Clarendon Press, 1989. ISBN 0-19-861232-X (vol. 20), ISBN 0-19-861186-2 (set.) or /\'ziːnɒn/xenon, entry in Dictionary.com Unabridged (v 1.1), accessed on line February 19, 2007. Transcribed into IPA.) is the chemical element that has the symbol Xe and atomic number 54. A colorless, heavy, odorless noble gas, xenon occurs in the earth\'s atmosphere in trace amounts.Staff (2007). Xenon. Columbia Electronic Encyclopedia. Columbia University Press. Retrieved on 2007-10-23. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.Husted, Robert; Boorman, Mollie (December 15 2003). Xenon. Los Alamos National Laboratory, Chemical Division. Retrieved on 2007-09-26.Rabinovich, Viktor Abramovich; Vasserman, A. A.; Nedostup, V. I.; Veksler, L. S. (1988). Thermophysical properties of neon, argon, krypton, and xenon, English-language edition, Washington, DC: Hemisphere Publishing Corp.. ISBN 0195218337. —National Standard Reference Data Service of the USSR. Volume 10.

Naturally occurring xenon consists of nine stable isotopes. There are also over 40 unstable isotopes that undergo radioactive decay. The isotope ratios of xenon are an important tool for studying the early history of the Solar System. Xenon-135 is produced as a result of nuclear fission and acts as a neutron absorber in nuclear reactors.

Xenon is used in flash lamps and arc lamps, and as a general anesthetic.Sanders, Robert D.; Ma, Daqing; Maze, Mervyn (2005). "Xenon: elemental anaesthesia in clinical practice". British Medical Bulletin 71 (1): 115-135. Retrieved on 2007-10-02.  The first excimer laser design used a xenon dimer molecule (Xe₂) as its lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is also being used to search for hypothetical weakly interacting massive particles and as the propellant for ion thrusters in spacecraft.

Contents 1 History 2 Occurrence 3 Characteristics 4 Isotopes 5 Compounds 6 Applications 6.1 Illumination and optics 6.1.1 Gas-discharge lamps 6.1.2 Lasers 6.2 Anesthesia 6.3 Medical imaging 6.4 Other 7 Precautions 8 See also 9 References 10 External links

History

Xenon was discovered in England by William Ramsay and Morris Travers on July 12, 1898, shortly after their discovery of the elements krypton and neon. They found it in the residue left over from evaporating components of liquid air.W. Ramsay and M. W. Travers (1898). "On the extraction from air of the companions of argon, and neon". Report of the Meeting of the British Association for the Advancement of Science: 828. Gagnon, Steve. It\'s Elemental - Xenon. Thomas Jefferson National Accelerator Facility. Retrieved on 2007-06-16. Ramsay suggested the name xenon for this gas from the Greek word ξένον [xenon], neuter singular form of ξένος [xenos], meaning foreign, strange, or host.Anonymous (1904). in Daniel Coit Gilman, Harry Thurston Peck, Frank Moore Colby: The New International Encyclopædia. Dodd, Mead and Company, p. 906. Staff (1991). The Merriam-Webster New Book of Word Histories. Merriam-Webster, Inc., p. 513. ISBN 0877796033.  In 1902, Ramsay estimated the proportion of xenon in the Earth\'s atmosphere as one part in 20 million.Ramsay, William (1902). "An Attempt to Estimate the Relative Amounts of Krypton and of Xenon in Atmospheric Air". Proceedings of the Royal Society of London 71: 421-426. Retrieved on 2007-10-02. 

During the 1930s, engineer Harold Edgerton began exploring strobe light technology for high speed photography. This led him to the invention of the xenon flash lamp, in which light is generated by sending a brief electrical current through a tube filled with xenon gas. In 1934, Edgerton was able to generate flashes as brief as one microsecond with this method.Anonymous. History. Millisecond Cinematography. Retrieved on 2007-11-07.Paschotta, Rüdiger (November 1, 2007). Lamp-pumped lasers. Encyclopedia of Laser Physics and Technology. RP Photonics. Retrieved on 2007-11-07.

In 1939 Albert R. Behnke Jr. began exploring the causes of "drunkenness" in deep-sea divers. He tested the effects of varying the breathing mixtures on his subjects, and discovered that this caused the divers to perceive a change in depth. From his results, he deduced that xenon gas could serve as an anesthetic. Although Lazharev, in Russia, apparently studied xenon anesthesia in 1941, the first published report confirming xenon anesthesia was in 1946 by J. H. Lawrence, who experimented on mice. Xenon was first used as a surgical anesthetic in 1951 by Stuart C. Cullen, who successfully operated on two patients.Marx, Thomas; Schmidt, Michael; Schirmer, Uwe; Reinelt, Helmut (2000). "Xenon anesthesia". Journal of the Royal Society of Medicine 93: 513-517. Retrieved on 2007-10-02. 

In 1960 physicist John H. Reynolds discovered that certain meteorites contained an isotopic anomaly in the form of an overabundance of xenon-129. He inferred that this was a decay product of radioactive iodine-129. This isotope is produced slowly by cosmic ray spallation and nuclear fission, but is produced in quantity only in supernova explosions. As the half-life of ¹²⁹I is comparatively short on a cosmological time scale, only 16 million years, this demonstrated that only a short time had passed between the supernova and the time the meteorites had solidified and trapped the ¹²⁹I. These two events (supernova and solidification of gas cloud) were inferred to have happened during the early history of the Solar System, as the ¹²⁹I isotope was likely generated before the Solar System was formed, but not long before, and seeded the solar gas cloud isotopes with isotopes from a second source. This supernova source may also have caused collapse of the solar gas cloud. Clayton, Donald D. (1983). Principles of Stellar Evolution and Nucleosynthesis, 2nd edition, University of Chicago Press, p. 75. ISBN 0226109534.  Bolt, B. A.; Packard, R. E.; Price, P. B. (2007). John H. Reynolds, Physics: Berkeley. The University of California, Berkeley. Retrieved on 2007-10-01.

Xenon and the other noble gases were for a long time considered to be completely chemically inert and not able to form compounds. However, while teaching at the University of British Columbia, Neil Bartlett discovered that the gas platinum hexafluoride (PtF₆) was a powerful oxidizing agent that could oxidize oxygen gas (O₂) to form dioxygenyl hexafluoroplatinate (O₂⁺[PtF₆]⁻).Neil Bartlett and D. H. Lohmann (March 1962). "Dioxygenyl hexafluoroplatinate (V), O₂⁺[PtF₆]⁻". Proceedings of the Chemical Society (3): 115. London: Chemical Society. doi:10.1039/PS9620000097.  Since O₂ and xenon have almost the same first ionization potential, Bartlett realized that platinum hexafluoride might also be able to oxidize xenon. On March 23, 1962, he mixed the two gases and produced the first known compound of a noble gas, xenon hexafluoroplatinate.Bartlett, N. (June 1962). "Xenon hexafluoroplatinate (V) Xe⁺[PtF₆]⁻". Proceedings of the Chemical Society (6): 218. London: Chemical Society. doi:10.1039/PS9620000197. Freemantel, Michael (August 25, 2003). Chemistry at its Most Beautiful. Chemical & Engineering News. Retrieved on 2007-09-13. Bartlett thought its composition to be Xe⁺[PtF₆]⁻, although later work has revealed that it was probably a mixture of various xenon-containing salts.Graham, L.; Graudejus, O., Jha N.K., and Bartlett, N. (2000). "Concerning the nature of XePtF₆". Coordination Chemistry Reviews 197: 321–334. doi:10.1016/S0010-8545(99)00190-3. p. 392, §11.4, Inorganic Chemistry, translated by Mary Eagleson and William Brewer, edited by Bernhard J. Aylett, San Diego: Academic Press, 2001, ISBN 0-12-352651-5; translation of Lehrbuch der Anorganischen Chemie, originally founded by A. F. Holleman, continued by Egon Wiberg, edited by Nils Wiberg, Berlin: de Gruyter, 1995, 34th edition, ISBN 3-11-012641-9.Steel, Joanna (2007). Biography of Neil Bartlett. College of Chemistry, University of California, Berkeley. Retrieved on 2007-10-25. Since then, many other xenon compounds have been discovered,Bartlett, Neil (September 8, 2003). "The Noble Gases". Chemical & Engineering News 81 (36). American Chemical Society. Retrieved on 2007-10-01.  and some compounds of the noble gases argon, krypton, and radon have been identified, including argon fluorohydride (HArF),Leonid Khriachtchev, Mika Pettersson, Nino Runeberg, Jan Lundell, and Markku Räsänen (August 24, 2000). "A stable argon compound". Nature 406: 874–876. doi:10.1038/35022551.  krypton difluoride (KrF₂),Lynch, C. T.; Summitt, R.; Sliker, A. (1980). CRC Handbook of Materials Science. CRC Press. ISBN 087819231X. D. R. MacKenzie (September 20, 1963). "Krypton Difluoride: Preparation and Handling". Science 141 (3586): 1171. doi:10.1126/science.141.3586.1171.  and radon fluoride.Paul R. Fields, Lawrence Stein, and Moshe H. Zirin (1962). "Radon Fluoride". Journal of the American Chemical Society 84 (21): 4164–4165. doi:10.1021/ja00880a048. 

Occurrence

Xenon is a trace gas in Earth\'s atmosphere, occurring at 0.087±0.001 parts per million (μL/L),Hwang, Shuen-Cheng; Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases", Kirk-Othmer Encyclopedia of Chemical Technology, 5th edition, Wiley. DOI:10.1002/0471238961.0701190508230114.a01. ISBN 047148511X.  and is also found in gases emitted from some mineral springs. Some radioactive species of xenon, for example, ¹³³Xe and ¹³⁵Xe, are produced by neutron irradiation of fissionable material within nuclear reactors.

Xenon is obtained commercially as a byproduct of the separation of air into oxygen and nitrogen. After this separation, generally performed by fractional distillation in a double-column plant, the liquid oxygen produced will contain small quantities of krypton and xenon. By additional fractional distillation steps, the liquid oxygen may be enriched to contain 0.1–0.2% of a krypton/xenon mixture, which is extracted either via adsorption onto silica gel or by distillation. Finally, the krypton/xenon mixture may be separated into krypton and xenon via distillation.Kerry, Frank G. (2007). Industrial Gas Handbook: Gas Separation and Purification. CRC Press, pp. 101–103. ISBN 0849390052.  Xenon - Xe. CFC StarTec LLC (August 10, 1998). Retrieved on 2007-09-07. Extraction of a liter of xenon from the atmosphere requires 220 watt-hours of energy.Singh, Sanjay (May 15, 2005). Xenon: A modern anaesthetic. Indian Express Newspapers Limited. Retrieved on 2007-10-10. Worldwide production of xenon in 1998 was estimated at 5,000–7,000 m³.Häussinger, Peter; Reinhard Glatthaar, Wilhelm Rhode, Helmut Kick, Christian Benkmann, Josef Weber, Hans-Jörg Wunschel, Viktor Stenke, Edith Leicht, Hermann Stenger (2001). "Noble Gases", Ullmann\'s Encyclopedia of Industrial Chemistry, 6th edition, Wiley. DOI:10.1002/14356007.a17_485. ISBN 3527201653.  Due to its low abundance, xenon is much more expensive than the lighter noble gases—approximate prices for the purchase of small quantities in Europe in 1999 were 10 €/L for xenon, 1 €/L for krypton, and 0.20 €/L for neon.

Xenon is relatively rare in the Sun\'s atmosphere, on Earth, and in asteroids and comets. The atmosphere of Mars shows a xenon abundance similar to that of Earth: 0.08 parts per million,Williams, David R. (September 1, 2004). Mars Fact Sheet. NASA. Retrieved on 2007-10-10. however Mars shows a higher proportion of ¹²⁹Xe than the Earth or the Sun. As this isotope is generated by radioactive decay, the result may indicate that Mars lost most of its primordial atmosphere, possibly within the first 100 million years after the planet was formed.Schilling, James. Why is the Martian atmosphere so thin and mainly carbon dioxide?. Mars Global Circulation Model Group. Retrieved on 2007-10-10. Zahnle, Kevin J. (1993). "Xenological constraints on the impact erosion of the early Martian atmosphere". Journal of Geophysical Research 98 (E6): 10,899–10,913. Retrieved on 2007-10-10.  By contrast, the planet Jupiter has an unusually high abundance of xenon in its atmosphere; about 2.6 times as much as the Sun.Mahaffy, P. R.; Niemann, H. B.; Alpert, A.; Atreya, S. K.; Demick, J.; Donahue, T. M.; Harpold, D. N.; Owen, T. C. (2000). "Noble gas abundance and isotope ratios in the atmosphere of Jupiter from the Galileo Probe Mass Spectrometer". Journal of Geophysical Research 105 (E6): 15061-15072. Retrieved on 2007-10-01.  This high abundance remains unexplained and may have been caused by an early and rapid buildup of planetesimals—small, subplanetary bodies—before the presolar disk began to heat up.Owen, Tobias; Mahaffy, Paul; Niemann, H. B.; Atreya, Sushil; Donahue, Thomas; Bar-Nun, Akiva; de Pater, Imke (1999). "A low-temperature origin for the planetesimals that formed Jupiter". Nature 402 (6759): 269-270. Retrieved on 2007-02-04.  (Otherwise, xenon would not have been trapped in the planetesimal ices.) Within the Solar System, the nucleon fraction for all isotopes of xenon is 1.56 × 10^-8, or one part in 64 million of the total mass.Arnett, David (1996). Supernovae and Nucleosynthesis. Princeton, New Jersey: Princeton University Press. ISBN 0-691-01147-8.  The problem of the low terrestrial xenon may potentially be explained by covalent bonding of xenon to oxygen within quartz, hence reducing the outgassing of xenon into the atmosphere.Chrystèle Sanloup et al (2005). "Retention of Xenon in Quartz and Earth\'s Missing Xenon". Science 310 (5751): 1174-1177. Retrieved on 2007-10-08. 

Unlike the lower mass noble gases, the normal stellar nucleosynthesis process inside a star does not form xenon. Elements more massive than iron-56 have a net energy cost to produce through fusion, so there is no energy gain for a star to create xenon.Clayton, Donald D. (1983). Principles of Stellar Evolution and Nucleosynthesis. University of Chicago Press. ISBN 0226109534.  Instead, many isotopes of xenon are formed during supernova explosions.Heymann, D.; Dziczkaniec, M. (March 19-23, 1979). "Xenon from intermediate zones of supernovae". Proceedings 10th Lunar and Planetary Science Conference: pp. 1943-1959, Houston, Texas: Pergamon Press, Inc.. Retrieved on 2007-10-02. 

Characteristics

An electron shell diagram for xenon. Note the eight electrons in the outer shell.

An atom of xenon is defined as having a nucleus with 54 protons. At standard temperature and pressure, pure xenon gas has a density of 5.761 kg/m³, about 4.5 times the surface density of the Earth\'s atmosphere, 1.217 kg/m³.Williams, David R. (April 19, 2007). Earth Fact Sheet. NASA. Retrieved on 2007-10-04. As a liquid, xenon has a density of up to 3.100 g/mL, with the density maximum occurring at the triple point.Aprile, Elena; Aleksey E. Bolotnikov, Tadayoshi Doke (2006). Noble Gas Detectors. Wiley-VCH, 8-9. ISBN 3527609636.  Under the same conditions, the density of solid xenon, 3.640 g/cm³, is larger than the average density of granite, 2.75 g/cm³. Using gigapascals of pressure, xenon has been forced into a metallic phase. Caldwell, W. A.; Nguyen, J., Pfrommer, B., Louie, S., and Jeanloz, R. (1997). "Structure, bonding and geochemistry of xenon at high pressures". Science 277: 930-933. 

Xenon is a member of the zero-valence elements that are called noble or inert gases. It is inert to most common chemical reactions (such as combustion, for example) because the outer valence shell contains eight electrons. This produces a stable, minimum energy configuration in which the outer electrons are tightly bound.Bader, Richard F.W.. An Introduction to the Electronic Structure of Atoms and Molecules. McMaster University. Retrieved on 2007-09-27. However, xenon can be oxidized by powerful oxidizing agents, and many xenon compounds have been synthesized.

In a gas-filled tube, xenon emits a blue or lavenderish glow when the gas is excited by electrical discharge. Xenon emits a band of emission lines that span the visual spectrum,Talbot, John. Spectra of Gas Discharges. Rheinisch-Westfälische Technische Hochschule Aachen. Retrieved on 2006-08-10. but the most intense lines occur in the region of blue light, which produces the coloration.Watts, William Marshall (1904). An Introduction to the Study of Spectrum Analysis. London: Longmans, Green, and co.. 

Isotopes

Main article: Isotopes of xenon

Naturally occurring xenon is made of nine stable isotopes. The isotopes ¹²⁴Xe, ¹³⁴Xe and ¹³⁶Xe are predicted to undergo double beta decay, but this has never been observed so they are considered to be stable.Lüscher, Roland (2006). Status of ßß-decay in Xenon. University of Sheffield. Retrieved on 2007-10-01. Barabash, A.S. (2002). "Average (Recommended) Half-Life Values for Two-Neutrino Double-Beta Decay". Czechoslovak Journal of Physics 52 (4): 567–573. Retrieved on 2007-10-01.  Besides these stable forms, there are over 40 unstable isotopes that have been studied. ¹²⁹Xe is produced by beta decay of ¹²⁹I, which has a half-life of 16 million years, while ^131mXe, ¹³³Xe, ^133mXe, and ¹³⁵Xe are some of the fission products of both ²³⁵U and ²³⁹Pu,Caldwell, Eric (January 2004). Periodic Table--Xenon. Resources on Isotopes. USGS. Retrieved on 2007-10-08. and therefore used as indicators of nuclear explosions. The various isotopes of xenon are produced from supernova explosions, red giant stars that have exhausted the hydrogen at their cores and entered the asymptotic giant branch, classical novae explosionsPignatari, M.; Gallino, R.; Straniero, O.; Davis, A. (2004). "The origin of xenon trapped in presolar mainstream SiC grains". Memorie della Societa Astronomica Italiana 75: 729–734. Retrieved on 2007-10-26.  and the radioactive decay of elements such as iodine, uranium and plutonium.

The artificial isotope ¹³⁵Xe is of considerable significance in the operation of nuclear fission reactors. ¹³⁵Xe has a huge cross section for thermal neutrons, 2.6×10⁶ barns,Stacey, Weston M. (2007). Nuclear Reactor Physics. Wiley-VCH, p. 213. ISBN 3527406794.  so it acts as a neutron absorber or "poison" that can slow or stop the chain reaction after a period of operation. This was discovered in the earliest nuclear reactors built by the American Manhattan Project for plutonium production. Fortunately the designers had made provisions in the design to increase the reactor\'s reactivity (the number of neutrons per fission that go on to fission other atoms of nuclear fuel).Staff. Hanford Becomes Operational. The Manhattan Project: An Interactive History. U.S. Department of Energy. Retrieved on 2007-10-10. ¹³⁵Xe reactor poisoning played a major role in the Chernobyl disaster.Jeremy I. Pfeffer and Shlomo Nir (2000). Modern Physics: An Introductory Text. Imperial College Press, pp. 421 ff.. ISBN 1860942504. 

Under adverse conditions, relatively high concentrations of radioactive xenon isotopes may be found emanating from nuclear reactors due to the release of fission products from cracked fuel rods,Laws, Edwards A. (2000). Aquatic Pollution: An Introductory Text. John Wiley and Sons, p. 505. ISBN 0471348759.  or fissioning of uranium in cooling water.Staff. "A Nuclear Nightmare", Time, April 9, 1979. Retrieved on 2007-10-09. 

Because xenon is a tracer for two parent isotopes, xenon isotope ratios in meteorites are a powerful tool for studying the formation of the solar system. The iodine-xenon method of dating gives the time elapsed between nucleosynthesis and the condensation of a solid object from the solar nebula. Xenon isotopic ratios such as ¹²⁹Xe/¹³⁰Xe and ¹³⁶Xe/¹³⁰Xe are also a powerful tool for understanding terrestrial differentiation and early outgassing.Kaneoka, Ichiro (1998). "Xenon\'s Inside Story". Science 280 (5365): 851-852. Retrieved on 2007-10-10.  Excess ¹²⁹Xe found in carbon dioxide well gases from New Mexico was believed to be from the decay of mantle-derived gases soon after Earth\'s formation.Boulos, M.S.; Manuel, O.K. (1971). "The xenon record of extinct radioactivities in the Earth.". Science 174: 1334-1336. 

Compounds

See also: Category:Xenon compounds

Xenon tetrafluoride

Xenon hexafluoroplatinate was the first chemical compound of xenon, synthesized in 1962. Following this, many additional compounds of xenon have been discovered. These include xenon difluoride (XeF₂), xenon tetrafluoride (XeF₄), xenon hexafluoride (XeF₆), xenon tetroxide (XeO₄), and sodium perxenate (Na₄XeO₆). A highly explosive compound, xenon trioxide (XeO₃), has also been made. Most of the more than 80Xenon. Periodic Table Online. CRC Press. Retrieved on 2007-10-08.Moody, G. J. (1974). "A Decade of Xenon Chemistry". Journal of Chemical Education 51: 628-630. Retrieved on 2007-10-16.  xenon compounds found to date contain electronegative fluorine or oxygen. When other atoms are bound (such as hydrogen or carbon), they are often part of a molecule containing fluorine or oxygen.Harding, Charlie J.; Janes, Rob (2002). Elements of the P Block. Royal Society of Chemistry. ISBN 0854046909.  Some compounds of xenon are colored but most are colorless.

In 1995, a group of scientists at the University of Helsinki in Finland (M. Räsänen and co-workers) announced the preparation of xenon dihydride (HXeH), and later xenon hydride-hydroxide (HXeOH), hydroxenoacetylene (HXeCCH), and other Xe-containing molecules. Gerber, R. B. (June 2004). "Formation of novel rare-gas molecules in low-temperature matrices". Annual Review of Physical Chemistry 55: 55–78. doi:10.1146/annurev.physchem.55.091602.094420. Bartlett, 2003. See the paragraph starting Many recent findings. Deuterated molecules, HXeOD and DXeOH, have also been produced.Pettersson, Mika; Khriachtchev, Leonid; Lundell, Jan; Räsänen, Markku (1999). "A Chemical Compound Formed from Water and Xenon: HXeOH". Journal of the American Chemical Society 121 (50): 11904-11905. Retrieved on 2007-10-10. 

XeF₄ crystals. 1962.

As well as compounds where xenon forms a chemical bond, xenon can form clathrates—substances where xenon atoms are trapped by the crystalline lattice of another compound. An example is xenon hydrate (Xe·5.75 H₂O), where xenon atoms occupy vacancies in a lattice of water molecules.A molecular theory of general anesthesia, Linus Pauling, Science 134, #3471 (July 7, 1961), pp. 15–21. Reprinted as pp. 1328–1334, Linus Pauling: Selected Scientific Papers, vol. 2, edited by Barclay Kamb et al. River Edge, New Jersey: World Scientific: 2001, ISBN 9810229402. The deuterated version of this hydrate has also been produced.Tomoko Ikeda, Shinji Mae, Osamu Yamamuro, Takasuke Matsuo, Susumu Ikeda, and Richard M. Ibberson (November 23, 2000). "Distortion of Host Lattice in Clathrate Hydrate as a Function of Guest Molecule and Temperature". Journal of Physical Chemistry A 104 (46): 10623–10630. doi:10.1021/jp001313j.  Such clathrate hydrates can occur naturally under conditions of high pressure, such as in Lake Vostok underneath the Antarctic ice sheet.McKay, C. P.; Hand, K. P.; Doran, P. T.; Andersen, D. T.; Priscu, J. C. (2003). "Clathrate formation and the fate of noble and biologically useful gases in Lake Vostok, Antarctica". Geophysical Letters 30 (13): 35. Retrieved on 2007-10-02.  Clathrate formation can be used to fractionally distill xenon, argon and krypton.Barrer, R. M.;Stuart, W. I. (1957). "Non-Stoichiometric Clathrate of Water". Proceedings of the Royal Society of London 243: 172–189.  Xenon can also form endohedral fullerene compounds, where a xenon atom is trapped inside a fullerene molecule. The xenon atom trapped in the fullerene can be monitored via ¹²⁹Xe nuclear magnetic resonance spectroscopy. Using this technique, chemical reactions on the fullerene molecule can be analyzed, due to the sensitivity of the chemical shift of the xenon atom to its environment. However, the xenon atom also has an electronic influence on the reactivity of the fullerene.Frunzi, Michael; Cross, R. James; Saunders, Martin (2007). "Effect of Xenon on Fullerene Reactions". Journal of the American Chemical Society 129. doi:10.1021/ja075568n. 

Applications

Although xenon is rare and relatively expensive to extract from the Earth\'s atmosphere, it still has a number of applications.

Illumination and optics

Gas-discharge lamps

Xenon in shaped Geissler tubes.

Xenon is used in light-emitting devices called xenon flash lamps, which are used in photographic flashes and stroboscopic lamps;Burke, James (2003). Twin Tracks: The Unexpected Origins of the Modern World. Oxford University Press, 33. ISBN 0743226194.  to excite the active medium in lasers which then generate coherent light;Staff (2007). Xenon Applications. Praxair Technology. Retrieved on 2007-10-04. and, occasionally, in bactericidal lamps.Baltás, E.; Csoma, Z.; Bodai, L.; Ignácz, F.; Dobozy, A.; Kemény, L. (2003). "A xenon-iodine electric discharge bactericidal lamp". Technical Physics Letters 29 (10): 871-872.  The first solid-state laser, invented in 1960, was pumped by a xenon flash lamp,Toyserkani, E.; Khajepour, A.; Corbin, S. (2004). Laser Cladding. CRC Press, 48. ISBN 0849321727.  and lasers used to power inertial confinement fusion are also pumped by xenon flash lamps.Skeldon, M.D.; Saager, R.; Okishev, A.; Seka, W. (1997). "Thermal distortions in laser-diode- and flash-lamp-pumped Nd:YLF laser rods". LLE Review 71: 137-144. Retrieved on 2007-02-04. 

Xenon short-arc lamp.

Continuous, short-arc, high pressure xenon arc lamps have a color temperature closely approximating noon sunlight and are used in solar simulators. That is, the chromaticity of these lamps closely approximates a heated black body radiator that has a temperature close to that observed from the Sun. After they were first introduced during the 1940s, these lamps began replacing the shorter-lived carbon arc lamps in movie projectors.Mellor, David (2000). Sound Person\'s Guide to Video. Focal Press, p. 186. ISBN 0240515951.  They are employed in typical 35mm and IMAX film projection systems, automotive HID headlights and other specialized uses. These arc lamps are an excellent source of short wavelength ultraviolet radiation and they have intense emissions in the near infrared, which is used in some night vision systems.

The individual cells in a plasma display use a mixture of xenon and neon that is converted into a plasma using electrodes. The interaction of this plasma with the electrodes generates ultraviolet photons, which then excite the phosphor coating on the front of the display.Anonymous. The plasma behind the plasma TV screen. Plasma TV Science. Retrieved on 2007-10-14.Marin, Rick. "Plasma TV: That New Object Of Desire", The New York Times, March 21, 2001. 

Xenon is used as a "starter gas" in high pressure sodium lamps. It has the lowest thermal conductivity and lowest ionization potential of all the non-radioactive noble gases. As a noble gas, it does not interfere with the chemical reactions occurring in the operating lamp. The low thermal conductivity minimizes thermal losses in the lamp while in the operating state, and the low ionization potential causes the breakdown voltage of the gas to be relatively low in the cold state, which allows the lamp to be more easily started.Waymouth, John (1971). Electric Discharge Lamps. Cambridge, MA: The M.I.T. Press. ISBN 0262230488. 

Lasers

In 1962, a group of researchers at Bell Laboratories discovered laser action in xenon,C. K. N. Patel, W. R. Bennett, Jr., W. L. Faust, and R. A. McFarlane (August 1, 1962). "Infrared spectroscopy using stimulated emission techniques". Physical Review Letters 9 (3): 102–104. doi:10.1103/PhysRevLett.9.102.  and later found that the laser gain was improved by adding helium to the lasing medium.C. K. N. Patel, W. L. Faust, and R. A. McFarlane (December 1, 1962). "High gain gaseous (Xe-He) optical masers". Applied Physics Letters 1: 84–85. doi:10.1063/1.1753707. W. R. Bennett, Jr. (1962). "Gaseous optical masers". Applied Optics Supplement 1: 24–61.  The first excimer laser used a xenon dimer (Xe₂) energized by a beam of electrons to produce stimulated emission at an ultraviolet wavelength of 176 nm.Basov, N. G.; Danilychev, V. A.; Popov, Yu. M. (1971). "Stimulated Emission in the Vacuum Ultraviolet Region". Soviet Journal of Quantum Electronics 1 (1): 18-22. doi:10.1070/QE1971v001n01ABEH003011.  Xenon chloride and xenon fluoride have also been used in excimer (or, more accurately, exciplex) lasers.Laser Output. University of Waterloo. Retrieved on 2007-10-07. The xenon chloride excimer laser has been employed, for example, in certain dermatological uses.E. Baltás, Z. Csoma, L. Bodai, F. Ignácz, A. Dobozy, and L. Kemény (July 2006). "Treatment of atopic dermatitis with the xenon chloride excimer laser". Journal of the European Academy of Dermatology and Venereology 20 (6): 657–660. doi:10.1111/j.1468-3083.2006.01495.x. 

Anesthesia

Xenon has been used as a general anaesthetic, although it is expensive. Even so, anesthesia machines that can deliver xenon are about to appear on the European market.Tonner, P. H. (2006). "Xenon: one small step for anaesthesia…? (editorial review)". Current Opinion in Anaesthesiology 19 (4): 382-384.  Two mechanisms for xenon anesthesia have been proposed. The first one involves the inhibition of the calcium ATPase pump—the mechanism cells use to remove calcium (Ca²⁺)—in the cell membrane of synapses.Franks, John J. MD; Horn, Jean-Louis MD; Janicki, Piotr K. MD, PhD; Singh, Gurkeerat PhD (1995). "Halothane, Isoflurane, Xenon, and Nitrous Oxide Inhibit Calcium ATPase Pump Activity in Rat Brain Synaptic Plasma Membranes.". Anesthesiology 82 (1): 108-117.  This results from a conformational change when xenon binds to nonpolar sites inside the protein.Lopez, Maria M.; Kosk-Kosicka, Danuta (1995). "How do volatile anesthetics inhibit Ca₂⁺-ATPases?". Journal of Biological Chemistry 270 (47): 28239-28245.  The second mechanism focuses on the non-specific interactions between the anesthetic and the lipid membrane.Heimburg, T.; Jackson A. D. (2007). "The thermodynamics of general anesthesia". Biophysical Journal 92 (9): 3159-65. doi:10.1529/biophysj.106.099754. 

Xenon has a minimum alveolar concentration (MAC) of 71%, making it 50% more potent than N₂O as an anesthetic. Thus it can be used in concentrations with oxygen that have a lower risk of hypoxia. Unlike nitrous oxide (N₂O), xenon is not a greenhouse gas and so it is also viewed as environmentally friendly. Because of the high cost of xenon, however, economic application will require a closed system so that the gas can be recycled, with the gas being appropriately filtered for contaminants between uses.

Medical imaging

Gamma emission from the radioisotope ¹³³Xe of xenon can be used to image the heart, lungs, and brain, for example, by means of single photon emission computed tomography. ¹³³Xe has also been used to measure blood flow.