Xenon, a heavy chemical element with the symbol Xe and atomic number 54, is a colorless, dense, odorless noble gas found in Earth's atmosphere in trace amounts.[1][2]


Xenon spectrum is 400 nm - 700 nm. Credit: McZusatz.{{free media}}

Xenon is a trace gas in Earth's atmosphere, occurring at 87±1 nL/L (parts per billion), or approximately 1 part per 11.5 million.[3]


Spectrum = gas discharge tube: the noble gas: xenon Xe. Used with 1,8kV, 18mA, 35kHz. ≈8" length. Credit: Alchemist-hp.{{free media}}

The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium energized by a beam of electrons to produce stimulated emission at an ultraviolet wavelength of 176 nm.[4]


An acrylic cube specially prepared for element collectors containing liquefied xenon. Credit: Rasiel Suarez on behalf of Luciteria LLC.{{free media}}

Liquid xenon has a high polarizability due to its large atomic volume, and thus is an excellent solvent. It can dissolve hydrocarbons, biological molecules, and even water.[5]


A layer of solid xenon floats on top of liquid xenon inside a high voltage apparatus. Credit: Solypewo.{{free media}}

Under the same conditions, the density of solid xenon, 3.640 g/cm3, is greater than the average density of granite, 2.75 g/cm3.[6] Under gigapascals of pressure, xenon forms a metallic phase.[7]

Solid xenon changes from (fcc) to (hcp) crystal phase under pressure and begins to turn metallic at about 140 GPa, with no noticeable volume change in the hcp phase. It is completely metallic at 155 GPa. When metallized, xenon appears sky blue because it absorbs red light and transmits other visible frequencies. Such behavior is unusual for a metal and is explained by the relatively small width of the electron bands in that state.[8][9]


Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System.[10] Radioactive xenon-135 is produced by beta decay from iodine-135 (a product of nuclear fission), and is the most significant (and unwanted) neutron absorber in nuclear reactors.[11]

List of xenon isotopes
Isotope Abundance Half-life Decay mode Product
0.095 % 1.8x1022y[12] εε 124
syn 16.9 h ε 125
0.089 % stable
syn 36.345 d ε 127
1.910 % stable
26.401 % stable
4.071 % stable
21.232 % stable
26.909 % stable
syn 5.247 d β− 133
10.436 % stable
syn 9.14 h β− 135
8.857 % 2.165x1021y[13] β−β− 136

Solar systemsEdit

Within the Solar System, the nucleon fraction of xenon is 1.56 × 10−8, for an abundance of approximately one part in 630 thousand of the total mass.[14] Xenon is relatively rare in the Sun's atmosphere, on Earth, and in asteroids and comets. The abundance of xenon in the atmosphere of planet Jupiter is unusually high, about 2.6 times that of the Sun.[15] Mass fraction calculated from the average mass of an atom in the solar system of about 1.29 atomic mass units. This abundance remains unexplained, but may have been caused by an early and rapid buildup of planetesimals—small, subplanetary bodies—before the heating of the presolar disk.[16] (Otherwise, xenon would not have been trapped in the planetesimal ices.) The problem of the low terrestrial xenon may be explained by covalent bonding of xenon to oxygen within quartz, reducing the outgassing of xenon into the atmosphere.[17]


Unlike the lower-mass noble gases, the normal stellar nucleosynthesis process inside a star does not form xenon. Elements more massive than iron-56 consume energy through fusion, and the synthesis of xenon represents no energy gain for a star.[18] Instead, xenon is formed during supernova explosions,[19] in classical nova explosions,[20] by the slow neutron-capture process (s-process) in red giant stars that have exhausted their core hydrogen and entered the asymptotic giant branch,[21] and from radioactive decay, for example by beta decay of extinct iodine-129 and spontaneous fission of thorium, uranium, and plutonium.[22]


This image of a xenon ion engine, photographed through a port of the vacuum chamber where it was being tested at NASA's Jet Propulsion Laboratory, shows the faint blue glow of charged atoms being emitted from the engine. Credit: NASA.{{free media}}


See alsoEdit


  1. Staff. (2007). "Xenon, In: Columbia Electronic Encyclopedia". (6th). Columbia University Press. Retrieved on 23 October 2007.
  2. xenon. San Francisco, California: Wikimedia Foundation, Inc. 5 October 2013. Retrieved 5 October 2013. 
  3. Hwang, Shuen-Cheng; Robert D. Lein; Daniel A. Morgan (2005). "Noble Gases". Kirk-Othmer Encyclopedia of Chemical Technology (5th ed.). John Wiley & Sons. doi:10.1002/0471238961.0701190508230114.a01. 
  4. 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. 
  5. Rentzepis, Peter M.; Douglass, D. C. (1981-09-10). "Xenon as a solvent". Nature 293 (5828): 165–166. doi:10.1038/293165a0. 
  6. Aprile, Elena; Bolotnikov, Aleksey E.; Doke, Tadayoshi (2006). Noble Gas Detectors. Wiley-VCH. pp. 8–9. 
  7. Caldwell, W. A.; Nguyen, J.; Pfrommer, B.; Louie, S.; Jeanloz, Raymond (1997). "Structure, bonding and geochemistry of xenon at high pressures". Science 277 (5328): 930–933. doi:10.1126/science.277.5328.930. 
  8. Fontes, E. "Golden Anniversary for Founder of High-pressure Program at CHESS". Cornell University. Retrieved 2009-05-30.
  9. Eremets, Mikhail I.; Gregoryanz, Eugene A.; Struzhkin, Victor V.; Mao, Ho-Kwang; Hemley, Russell J.; Mulders, Norbert; Zimmerman, Neil M. (2000). "Electrical Conductivity of Xenon at Megabar Pressures". Physical Review Letters 85 (13): 2797–800. doi:10.1103/PhysRevLett.85.2797. PMID 10991236. 
  10. Kaneoka, Ichiro (1998). "Xenon's Inside Story". Science 280 (5365): 851–852. doi:10.1126/science.280.5365.851b. 
  11. Stacey, Weston M. (2007). Nuclear Reactor Physics. Wiley-VCH. p. 213. ISBN 978-3-527-40679-1. 
  12. "Observation of two-neutrino double electron capture in 124
    with XENON1T". Nature. 568 (7753): 532–535. 2019. doi:10.1038/s41586-019-1124-4.
  13. Albert, J. B.; Auger, M.; Auty, D. J.; Barbeau, P. S.; Beauchamp, E.; Beck, D.; Belov, V.; Benitez-Medina, C.; Bonatt, J.; Breidenbach, M.; Brunner, T.; Burenkov, A.; Cao, G. F.; Chambers, C.; Chaves, J.; Cleveland, B.; Cook, S.; Craycraft, A.; Daniels, T.; Danilov, M.; Daugherty, S. J.; Davis, C. G.; Davis, J.; Devoe, R.; Delaquis, S.; Dobi, A.; Dolgolenko, A.; Dolinski, M. J.; Dunford, M.; et al. (2014). "Improved measurement of the 2νββ half-life of 136Xe with the EXO-200 detector". Physical Review C. 89. arXiv:1306.6106. Bibcode:2014PhRvC..89a5502A. doi:10.1103/PhysRevC.89.015502.
  14. Arnett, David (1996). Supernovae and Nucleosynthesis. Princeton, New Jersey: Princeton University Press. ISBN 0-691-01147-8. 
  15. 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. doi:10.1029/1999JE001224. 
  16. 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): 269–70. doi:10.1038/46232. PMID 10580497. 
  17. Sanloup, Chrystèle (2005). "Retention of Xenon in Quartz and Earth's Missing Xenon". Science 310 (5751): 1174–7. doi:10.1126/science.1119070. PMID 16293758. 
  18. Clayton, Donald D. (1983). Principles of Stellar Evolution and Nucleosynthesis. University of Chicago Press. p. 604. 
  19. Heymann, D.; Dziczkaniec, M. (March 19–23, 1979). Xenon from intermediate zones of supernovae. Proceedings 10th Lunar and Planetary Science Conference. Houston, Texas: Pergamon Press, Inc. pp. 1943–1959. Bibcode:1979LPSC...10.1943H.
  20. Pignatari, 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. 
  21. Beer, H.; Kaeppeler, F.; Reffo, G.; Venturini, G. (November 1983). "Neutron capture cross-sections of stable xenon isotopes and their application in stellar nucleosynthesis". Astrophysics and Space Science 97 (1): 95–119. doi:10.1007/BF00684613. 
  22. Caldwell, Eric (January 2004). "Periodic Table – Xenon". Resources on Isotopes. USGS. Retrieved 2007-10-08.

External linksEdit