Editing Xenon (section)

== Compounds ==
{{Category see also|Xenon compounds}}
After Neil Bartlett's discovery in 1962 that xenon can form chemical compounds, a large number of xenon compounds have been discovered and described. Almost all known xenon compounds contain the [[electronegative]] atoms fluorine or oxygen. The chemistry of xenon in each oxidation state is analogous to that of the neighboring element [[iodine]] in the immediately lower oxidation state.<ref name="harding1" />

=== Halides ===
[[File:Xenon-tetrafluoride-3D-vdW.png|thumb|[[Xenon tetrafluoride]] | alt=A model of planar chemical molecule with a blue center atom (Xe) symmetrically bonded to four peripheral atoms (fluorine).]]
[[File:Xenon tetrafluoride.png|thumb|XeF<sub>4</sub> crystals, 1962|alt=Many cubic transparent crystals in a petri dish.]]

Three [[fluoride]]s are known: [[xenon difluoride|{{chem|XeF|2}}]], [[xenon tetrafluoride|{{chem|XeF|4}}]], and [[xenon hexafluoride|{{chem|XeF|6}}]]. XeF is theorized to be unstable.<ref>{{Cite journal
| title   = Probable nonexistence of xenon monofluoride as a chemically bound species in the gas phase
| author  = Dean H Liskow
| author2 = Henry F Schaefer III
| author3 = Paul S Bagus
| author4 = Bowen Liu
| journal = J Am Chem Soc
| year    = 1973
| volume  = 95
| issue   = 12
| pages   = 4056–57
| doi     = 10.1021/ja00793a042
| bibcode = 1973JAChS..95.4056L
}}</ref> These are the starting points for the synthesis of almost all xenon compounds.

The solid, crystalline difluoride {{chem|XeF|2}} is formed when a mixture of [[fluorine]] and xenon gases is exposed to ultraviolet light.<ref>{{cite journal
| last    = Weeks
| first   = James L.
| author2 = Chernick, Cedric
| author3 = Matheson, Max S.
| title   = Photochemical Preparation of Xenon Difluoride
| journal = Journal of the American Chemical Society
| volume  = 84
| issue   = 23
| pages   = 4612–13
| doi     = 10.1021/ja00882a063
| year    = 1962
| bibcode = 1962JAChS..84.4612W
}}</ref> The ultraviolet component of ordinary daylight is sufficient.<ref>{{cite journal
| author  = Streng, L. V.
| author2 = Streng, A. G.
| title   = Formation of Xenon Difluoride from Xenon and Oxygen Difluoride or Fluorine in Pyrex Glass at Room Temperature
| journal = Inorganic Chemistry
| year    = 1965
| volume  = 4
| issue   = 9
| pages   = 1370–71
| doi     = 10.1021/ic50031a035
}}</ref> Long-term heating of {{chem|XeF|2}} at high temperatures under an {{chem|NiF|2}} catalyst yields {{chem|XeF|6}}.<ref name="tramsek">{{cite journal
| author  = Tramšek, Melita
| author2 = Žemva, Boris
| title   = Synthesis, Properties and Chemistry of Xenon(II) Fluoride
| journal = Acta Chimica Slovenica
| date    = December 5, 2006
| volume  = 53
| issue   = 2
| pages   = 105–16
| doi     = 10.1002/chin.200721209
}}</ref> Pyrolysis of {{chem|XeF|6}} in the presence of [[sodium fluoride|NaF]] yields high-purity {{chem|XeF|4}}.<ref>{{cite journal
| author  = Ogrin, Tomaz
| author2 = Bohinc, Matej
| author3 = Silvnik, Joze
| title   = Melting-point determinations of xenon difluoride-xenon tetrafluoride mixtures
| journal = [[Journal of Chemical and Engineering Data]]
| year    = 1973
| volume  = 18
| issue   = 4
| page    = 402
| doi     = 10.1021/je60059a014
}}</ref>

The xenon fluorides behave as both fluoride acceptors and fluoride donors, forming salts that contain such cations as {{chem |XeF|+}} and {{chem |Xe}}{{su |b= 2}}{{chem |F|3|+}}, and anions such as {{chem |XeF|5|-}}, {{chem |XeF|7|-}}, and {{chem |XeF|8|2-}}.  The green, paramagnetic {{chem |Xe|2|+}} is formed by the reduction of {{chem|XeF|2}} by xenon gas.<ref name="harding1">{{cite book
| author    = Harding, Charlie
| author2   = Johnson, David Arthur
| author3   = Janes, Rob
| title     = Elements of the ''p'' block
| pages     = 93–94
| publisher = Royal Society of Chemistry
| location  = Great Britain
| date      = 2002
| isbn      = 0-85404-690-9
| url       = https://books.google.com/books?id=W0HW8wgmQQsC&pg=PA93
}}</ref>

{{chem|XeF|2}} also forms [[complex (chemistry)|coordination complexes]] with transition metal ions. More than 30 such complexes have been synthesized and characterized.<ref name="tramsek" />

Whereas the xenon fluorides are well characterized, the other halides are not.  [[Xenon dichloride]], formed by the high-frequency irradiation of a mixture of xenon, fluorine, and [[silicon tetrachloride|silicon]] or [[carbon tetrachloride]],<ref name="scott1">{{cite encyclopedia
| title        = Xenon Compounds
| encyclopedia = Concise encyclopedia chemistry
| publisher    = [[Walter de Gruyter]]
| url          = https://books.google.com/books?id=Owuv-c9L_IMC&pg=PA1183
| year         = 1994
| page         = 1183
| isbn         = 3-11-011451-8
| author       = Scott, Thomas
| author2      = Eagleson, Mary
}}</ref> is reported to be an endothermic, colorless, crystalline compound that decomposes into the elements at 80&nbsp;°C. However, {{chem|XeCl|2}} may be merely a [[van der Waals molecule]] of weakly bound Xe atoms and {{chem |Cl|2}} molecules and not a real compound.<ref>{{cite journal
| author  = Proserpio, Davide M.
| author2 = Hoffmann, Roald
| author3 = Janda, Kenneth C.
| title   = The xenon-chlorine conundrum: van der Waals complex or linear molecule?
| year    = 1991
| volume  = 113
| journal = Journal of the American Chemical Society
| issue   = 19
| pages   = 7184–89
| doi     = 10.1021/ja00019a014
| bibcode = 1991JAChS.113.7184P
}}</ref> Theoretical calculations indicate that the linear molecule {{chem|XeCl|2}} is less stable than the van der Waals complex.<ref>{{cite journal
| author  = Richardson, Nancy A.
| author2 = Hall, Michael B.
| year    = 1993
| title   = The potential energy surface of xenon dichloride
| journal = The Journal of Physical Chemistry
| volume  = 97
| issue   = 42
| pages   = 10952–54
| doi     = 10.1021/j100144a009
}}</ref> [[Xenon tetrachloride]] and [[xenon dibromide]] are even more unstable and they cannot be synthesized by chemical reactions. They were created by [[radioactive decay]] of {{chem |129|ICl|4|-}} and {{chem |129|IBr|2|-}}, respectively.<ref name="book bell2013syntheses">{{cite book
| title     = Syntheses and Physical Studies of Inorganic Compounds
| author    = Bell, C.F.
| isbn      = 978-1-4832-8060-8
| year      = 2013
| page      = 143
| publisher = Elsevier Science
}}</ref><ref name="book cockett2013chemistry">{{Cite book
| title     = The Chemistry of the Monatomic Gases: Pergamon Texts in Inorganic Chemistry
| author1   = Cockett, A.H.
| author2   = Smith, K.C.
| author3   = Bartlett, N.
| isbn      = 978-1-4831-5736-8
| year      = 2013
| page      = 292
| publisher = Elsevier Science
}}</ref>

=== Oxides and oxohalides ===
Three oxides of xenon are known: [[xenon trioxide]] ({{chem|XeO|3}}) and [[xenon tetroxide]] ({{chem|XeO|4}}), both of which are dangerously explosive and powerful oxidizing agents, and [[xenon dioxide]] (XeO<sub>2</sub>), which was reported in 2011 with a [[coordination number]] of four.<ref>{{cite journal
| author  = Brock, D.S.
| author2 = Schrobilgen, G.J.
| title   = Synthesis of the missing oxide of xenon, XeO<sub>2</sub>, and its implications for Earth's missing xenon
| journal = [[Journal of the American Chemical Society]]
| year    = 2011
| doi     = 10.1021/ja110618g
| volume  = 133
| issue   = 16
| pmid    = 21341650
| pages   = 6265–9
| bibcode = 2011JAChS.133.6265B
}}</ref> XeO<sub>2</sub> forms when xenon tetrafluoride is poured over ice. Its crystal structure may allow it to replace silicon in silicate minerals.<ref name="ChemistryWhere2011">{{Cite journal
| title      = Chemistry: Where did the xenon go?
| journal    = Nature
| volume     = 471
| issue      = 7337
| pages      = 138
| year       = 2011
| doi        = 10.1038/471138d
| bibcode    = 2011Natur.471T.138.
| doi-access = free
}}</ref> The XeOO<sup>+</sup> cation has been identified by [[infrared spectroscopy]] in solid [[argon]].<ref>{{cite journal
| author  = Zhou, M.
| author2 = Zhao, Y.
| author3 = Gong, Y.
| author4 = Li, J.
| title   = Formation and Characterization of the XeOO<sup>+</sup> Cation in Solid Argon
| journal = [[Journal of the American Chemical Society]]
| year    = 2006
| volume  = 128
| issue   = 8
| pmid    = 16492012
| pages   = 2504–5
| doi     = 10.1021/ja055650n
| bibcode = 2006JAChS.128.2504Z
}}</ref>

Xenon does not react with oxygen directly; the trioxide is formed by the hydrolysis of {{chem|XeF|6}}:<ref>{{cite book
| first     = John H.
| last      = Holloway
| author2   = Hope, Eric G.
| editor    = A. G. Sykes
| date      = 1998
| publisher = Academic
| title     = Advances in Inorganic Chemistry Press
| isbn      = 0-12-023646-X
| page      = 65
| url       = https://books.google.com/books?id=6iqXRtz6p3QC&pg=PA65
}}</ref>
: {{chem|XeF|6}} + 3 {{chem|H|2|O}} → {{chem|XeO|3}} + 6 HF

{{chem|XeO|3}} is weakly acidic, dissolving in alkali to form unstable ''xenate'' salts containing the {{chem|HXeO|4|−}} anion. These unstable salts easily [[disproportionation|disproportionate]] into xenon gas and [[perxenate]] salts, containing the {{chem|XeO|6|4−}} anion.<ref name="henderson">{{cite book
| first     = W.
| last      = Henderson
| title     = Main group chemistry
| date      = 2000
| publisher = [[Royal Society of Chemistry]]
| pages     = 152–53
| location  = Great Britain
| isbn      = 0-85404-617-8
| url       = https://books.google.com/books?id=twdXz1jfVOsC&pg=PA152
}}</ref>

Barium perxenate, when treated with concentrated [[sulfuric acid]], yields gaseous xenon tetroxide:<ref name="scott1" />
: {{chem|Ba|2|XeO|6}} + 2 {{chem|H|2|SO|4}} → 2 {{chem|BaSO|4}} + 2 {{chem|H|2|O}} + {{chem|XeO|4}}

To prevent decomposition, the xenon tetroxide thus formed is quickly cooled into a pale-yellow solid. It explodes above −35.9&nbsp;°C into xenon and oxygen gas, but is otherwise stable.

A number of xenon oxyfluorides are known, including {{chem|XeOF|2}}, [[xenon oxytetrafluoride|{{chem|XeOF|4}}]], {{chem|XeO|2|F|2}}, and {{chem|XeO|3|F|2}}. {{chem |XeOF|2}} is formed by reacting [[oxygen difluoride|{{chem|OF|2}}]] with xenon gas at low temperatures. It may also be obtained by partial hydrolysis of {{chem|XeF|4}}. It disproportionates at −20&nbsp;°C into {{chem|XeF|2}} and {{chem|XeO|2|F|2}}.<ref name="mackay1">{{cite book
| author    = Mackay, Kenneth Malcolm
| author2   = Mackay, Rosemary Ann
| author3   = Henderson, W.
| title     = Introduction to modern inorganic chemistry
| date      = 2002
| edition   = 6th
| publisher = CRC Press
| isbn      = 0-7487-6420-8
| url       = https://books.google.com/books?id=LpJPWKT3PNcC&pg=PA497
| pages     = 497–501
}}</ref> {{chem |XeOF|4}} is formed by the partial hydrolysis of {{chem |XeF|6}}...<ref>{{cite journal
| last    = Smith
| first   = D. F.
| s2cid   = 42752536
| year    = 1963
| title   = Xenon Oxyfluoride
| pmid    = 17810680
| journal = Science
| volume  = 140
| doi     = 10.1126/science.140.3569.899
| issue   = 3569
| bibcode = 1963Sci...140..899S
| pages   = 899–900
}}</ref>
:{{chem |XeF|6}} + {{chem |H|2|O}} → {{chem |XeOF|4}} + 2 {{chem |H|F}}
...or the reaction of {{chem|XeF|6}} with sodium perxenate, {{chem |Na|4|XeO|6}}. The latter reaction also produces a small amount of {{chem|XeO|3|F|2}}.

{{chem |Xe|O|2|F|2}} is also formed by partial hydrolysis of {{chem |Xe|F|6}}.<ref>{{cite book
| title     = Chemistry Textbook Part – 1 for Class XII
| publisher = NCERT
| isbn      = 978-81-7450-648-1
| page      = 204
| edition   = October 2022
| url       = https://ncert.nic.in/ncerts/l/lech107.pdf
| language  = English
| chapter   = P Block Elements
| date      = 2007
}}</ref>
:{{chem |Xe|F|6}} + 2 {{chem |H|2|O}} → {{chem |Xe|O|2|F|2}} + 4 {{chem |HF}}
{{chem|XeOF|4}} reacts with [[caesium fluoride|CsF]] to form the {{chem |XeOF|5|−}} anion,<ref name="mackay1" /><ref>{{cite journal
| title   = On the Structure of the [XeOF<sub>5</sub>]<sup>−</sup> Anion and of Heptacoordinated Complex Fluorides Containing One or Two Highly Repulsive Ligands or Sterically Active Free Valence Electron Pairs
| author  = Christe, K. O.
| author2 = Dixon, D. A.
| author3 = Sanders, J. C. P.
| author4 = Schrobilgen, G. J.
| author5 = Tsai, S. S.
| author6 = Wilson, W. W.
| journal = [[Inorganic Chemistry (journal)|Inorg. Chem.]]
| year    = 1995
| volume  = 34
| issue   = 7
| pages   = 1868–1874
| doi     = 10.1021/ic00111a039
}}</ref> while XeOF<sub>3</sub> reacts with the alkali metal fluorides [[potassium fluoride|KF]], [[rubidium fluoride|RbF]] and CsF to form the {{chem|XeOF|4|−}} anion.<ref>{{cite journal
| title   = Chlorine trifluoride oxide. V. Complex formation with Lewis acids and bases
| author  = Christe, K. O.
| author2 = Schack, C. J.
| author3 = Pilipovich, D.
| journal = [[Inorganic Chemistry (journal)|Inorg. Chem.]]
| year    = 1972
| volume  = 11
| issue   = 9
| pages   = 2205–2208
| doi     = 10.1021/ic50115a044
}}</ref>

=== Other compounds ===
Xenon can be directly bonded to a less electronegative element than fluorine or oxygen, particularly [[carbon]].<ref>{{cite book
| title     = Advances in Inorganic Chemistry
| author    = Holloway, John H.
| author2   = Hope, Eric G.
| others    = Contributor A. G. Sykes
| publisher = Academic Press
| year      = 1998
| isbn      = 0-12-023646-X
| url       = https://books.google.com/books?id=6iqXRtz6p3QC&pg=PA61
| pages     = 61–90
}}</ref> Electron-withdrawing groups, such as groups with fluorine substitution, are necessary to stabilize these compounds.<ref name="henderson" /> Numerous such compounds have been characterized, including:<ref name="mackay1" /><ref>{{cite journal
| title   = C<sub>6</sub>F<sub>5</sub>XeF, a versatile starting material in xenon–carbon chemistry
| year    = 2004
| last1   = Frohn
| first1  = H.
| journal = Journal of Fluorine Chemistry
| volume  = 125
| issue   = 6
| pages   = 981–988
| doi     = 10.1016/j.jfluchem.2004.01.019
| last2   = Theißen
| first2  = Michael
}}</ref>
* {{chem|C|6|F|5|–Xe|+|–N≡C–CH|3}}, where C<sub>6</sub>F<sub>5</sub> is the pentafluorophenyl group.
* {{chem|[C|6|F|5|]|2|Xe}}
* {{chem|C|6|F|5|–Xe–C≡N}}
* {{chem|C|6|F|5|–Xe–F}}
* {{chem|C|6|F|5|–Xe–Cl}}
* {{chem|C|2|F|5|–C≡C–Xe|+}}
* {{chem|[C|H|3|]|3|C–C≡C–Xe|+}}
* {{chem|C|6|F|5|–XeF|2|+}}
* {{chem|(C|6|F|5|Xe)|2|Cl|+}}

Other compounds containing xenon bonded to a less electronegative element include {{chem|F–Xe–N(SO|2|F)|2}} and {{chem|F–Xe–BF|2}}. The latter is synthesized from [[dioxygenyl]] tetrafluoroborate, {{chem|O|2|BF|4}}, at −100&nbsp;°C.<ref name="mackay1" /><ref>{{cite journal
| doi     = 10.1021/ja00764a022
| title   = Reaction of xenon with dioxygenyl tetrafluoroborate. Preparation of FXe-BF<sub>2</sub>
| date    = 1972
| last    = Goetschel
| first   = Charles T.
| author2 = Loos, Karl R.
| journal = Journal of the American Chemical Society
| volume  = 94
| issue   = 9
| pages   = 3018–3021
| bibcode = 1972JAChS..94.3018G
}}</ref>

An unusual ion containing xenon is the [[tetraxenonogold(II)]] cation, {{chem|AuXe|4|2+}}, which contains Xe–Au bonds.<ref name="waikeeli2">{{cite book
| title     = Advanced Structural Inorganic Chemistry
| author    = Li, Wai-Kee
| author2   = Zhou, Gong-Du
| author3   = Mak, Thomas C. W.
| editor    = Gong-Du Zhou
| editor2   = Thomas C. W. Mak
| publisher = [[Oxford University Press]]
| date      = 2008
| isbn      = 978-0-19-921694-9
| url       = https://books.google.com/books?id=2qAa5hp6KX4C&pg=PA678
| page      = 678
}}</ref> This ion occurs in the compound {{chem|AuXe|4|(Sb|2|F|11|)|2}}, and is remarkable in having direct chemical bonds between two notoriously unreactive atoms, xenon and [[gold]], with xenon acting as a transition metal ligand. A similar mercury complex (HgXe)(Sb<sub>3</sub>F<sub>17</sub>) (formulated as [HgXe<sup>2+</sup>][Sb<sub>2</sub>F<sub>11</sub><sup>–</sup>][SbF<sub>6</sub><sup>–</sup>]) is also known.<ref>{{Cite journal
| last1    = Hwang
| first1   = In-Chul
| last2    = Seidel
| first2   = Stefan
| last3    = Seppelt
| first3   = Konrad
| date     = September 22, 2003
| title    = Gold( I ) and Mercury( II ) Xenon Complexes
| url      = https://onlinelibrary.wiley.com/doi/10.1002/anie.200351208
| journal  = Angewandte Chemie International Edition
| language = en
| volume   = 42
| issue    = 36
| pages    = 4392–4395
| doi      = 10.1002/anie.200351208
| pmid     = 14502720
| issn     = 1433-7851
}}</ref>

The compound {{chem|Xe|2|Sb|2|F|11}} contains a Xe–Xe bond, the longest element-element bond known (308.71&nbsp;pm = 3.0871&nbsp;[[Angstrom|Å]]).<ref>{{cite book
| title      = Advanced Structural Inorganic Chemistry
| url        = https://archive.org/details/advancedstructur00liwa
| url-access = limited
| first1     = Wai-Kee
| last1      = Li
| first2     = Gong-Du
| last2      = Zhou
| first3     = Thomas C. W.
| last3      = Mak
| publisher  = Oxford University Press
| date       = 2008
| isbn       = 978-0-19-921694-9
| page       = [https://archive.org/details/advancedstructur00liwa/page/n696 674]
}}</ref>

In 1995, M. Räsänen and co-workers, scientists at the [[University of Helsinki]] in [[Finland]], announced the preparation of xenon dihydride (HXeH), and later xenon hydride-hydroxide (HXeOH), hydroxenoacetylene (HXeCCH), and other Xe-containing molecules.<ref>{{cite journal
| last    = Gerber
| first   = R. B.
| date    = 2004
| doi     = 10.1146/annurev.physchem.55.091602.094420
| title   = Formation of novel rare-gas molecules in low-temperature matrices
| journal = Annual Review of Physical Chemistry
| volume  = 55
| issue   = 1
| pages   = 55–78
| pmid    = 15117247
| bibcode = 2004ARPC...55...55G
}}</ref> In 2008, Khriachtchev ''et al.'' reported the preparation of HXeOXeH by the [[photolysis]] of water within a [[cryogenic]] xenon matrix.<ref>{{cite journal
| last    = Khriachtchev
| first   = Leonid
| author2 = Isokoski, Karoliina
| author3 = Cohen, Arik
| author4 = Räsänen, Markku
| author5 = Gerber, R. Benny
| title   = A Small Neutral Molecule with Two Noble-Gas Atoms: HXeOXeH
| journal = Journal of the American Chemical Society
| year    = 2008
| volume  = 130
| issue   = 19
| pages   = 6114–8
| doi     = 10.1021/ja077835v
| pmid    = 18407641
| bibcode = 2008JAChS.130.6114K
}}</ref> [[Deuterium|Deuterated]] molecules, HXeOD and DXeOH, have also been produced.<ref>{{cite journal
| last    = Pettersson
| first   = Mika
| author2 = Khriachtchev, Leonid
| author3 = Lundell, Jan
| author4 = Räsänen, Markku
| title   = A Chemical Compound Formed from Water and Xenon: HXeOH
| date    = 1999
| journal = Journal of the American Chemical Society
| volume  = 121
| issue   = 50
| pages   = 11904–905
| doi     = 10.1021/ja9932784
| bibcode = 1999JAChS.12111904P
}}</ref>

=== Clathrates and excimers ===
{{See also|Excimer laser}}
In addition to compounds where xenon forms a [[chemical bond]], xenon can form [[clathrate]]s—substances where xenon atoms or pairs are trapped by the [[Crystal structure|crystalline lattice]] of another compound. One example is [[xenon hydrate]] (Xe·{{frac|5|3|4}}H<sub>2</sub>O), where xenon atoms occupy vacancies in a lattice of water molecules.<ref>{{cite journal
| doi         = 10.1126/science.134.3471.15
| title       = A molecular theory of general anesthesia
| author-link = Linus Pauling
| journal     = Science
| volume      = 134
| issue       = 3471
| year        = 1961
| pages       = 15–21
| pmid        = 13733483
| last        = Pauling
| first       = L.
| bibcode     = 1961Sci...134...15P
}} Reprinted as {{cite book
| pages     = 1328–34
| title     = Linus Pauling: Selected Scientific Papers
| volume    = 2
| editor    = Pauling, Linus
| editor2   = Kamb, Barclay
| place     = River Edge, NJ
| publisher = World Scientific
| year      = 2001
| isbn      = 981-02-2940-2
| url       = https://books.google.com/books?id=2QduA19d_X8C&pg=PA1329
}}</ref> This clathrate has a melting point of 24&nbsp;°C.<ref name="henderson2">{{cite book
| title     = Main group chemistry
| last      = Henderson
| first     = W.
| date      = 2000
| publisher = Royal Society of Chemistry
| location  = Great Britain
| isbn      = 0-85404-617-8
| url       = https://books.google.com/books?id=twdXz1jfVOsC&pg=PA148
| page      = 148
}}</ref> The [[deuterate]]d version of this hydrate has also been produced.<ref>{{cite journal
| first   = Tomoko
| last    = Ikeda
| author2 = Mae, Shinji
| author3 = Yamamuro, Osamu
| author4 = Matsuo, Takasuke
| author5 = Ikeda, Susumu
| author6 = Ibberson, Richard M.
| title   = Distortion of Host Lattice in Clathrate Hydrate as a Function of Guest Molecule and Temperature
| journal = Journal of Physical Chemistry A
| date    = November 23, 2000
| volume  = 104
| issue   = 46
| pages   = 10623–30
| doi     = 10.1021/jp001313j
| bibcode = 2000JPCA..10410623I
}}</ref> Another example is xenon [[hydride]] (Xe(H<sub>2</sub>)<sub>8</sub>), in which xenon pairs ([[Dimer (chemistry)|dimers]]) are trapped inside [[solid hydrogen]].<ref name="KrH">{{cite journal
| doi        = 10.1038/srep04989
| title      = New high-pressure van der Waals compound Kr(H<sub>2</sub>)<sub>4</sub> discovered in the krypton-hydrogen binary system
| journal    = Scientific Reports
| volume     = 4
| page       = 4989
| year       = 2014
| last1      = Kleppe
| first1     = Annette K.
| last2      = Amboage
| first2     = Mónica
| last3      = Jephcoat
| first3     = Andrew P.
| bibcode    = 2014NatSR...4.4989K
| doi-access = free
}}</ref> Such [[clathrate hydrate]]s can occur naturally under conditions of high pressure, such as in [[Lake Vostok]] underneath the [[Antarctica|Antarctic]] ice sheet.<ref>{{cite journal
| last    = McKay
| first   = C. P.
| author2 = Hand, K. P.
| author3 = Doran, P. T.
| author4 = Andersen, D. T.
| author5 = Priscu, J. C.
| title   = Clathrate formation and the fate of noble and biologically useful gases in Lake Vostok, Antarctica
| journal = Geophysical Research Letters
| date    = 2003
| volume  = 30
| issue   = 13
| page    = 35
| doi     = 10.1029/2003GL017490
| bibcode = 2003GeoRL..30.1702M
| s2cid   = 20136021
}}</ref> Clathrate formation can be used to fractionally distill xenon, argon and krypton.<ref>{{cite journal
| last    = Barrer
| first   = R. M.
| author2 = Stuart, W. I.
| s2cid   = 97577041
| title   = Non-Stoichiometric Clathrate of Water
| journal = Proceedings of the Royal Society of London
| year    = 1957
| volume  = 243
| issue   = 1233
| pages   = 172–89
| doi     = 10.1098/rspa.1957.0213
| bibcode = 1957RSPSA.243..172B
}}</ref>

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 observed by <sup>129</sup>Xe [[nuclear magnetic resonance]] (NMR) spectroscopy. Through the sensitive [[chemical shift]] of the xenon atom to its environment, chemical reactions on the fullerene molecule can be analyzed. These observations are not without caveat, however, because the xenon atom has an electronic influence on the reactivity of the fullerene.<ref>{{cite journal
| last    = Frunzi
| first   = Michael
| author2 = Cross, R. James
| author3 = Saunders, Martin
| title   = Effect of Xenon on Fullerene Reactions
| journal = Journal of the American Chemical Society
| date    = 2007
| pmid    = 17924634
| volume  = 129
| doi     = 10.1021/ja075568n
| issue   = 43
| pages   = 13343–6
| bibcode = 2007JAChS.12913343F
| url     = https://figshare.com/articles/journal_contribution/2977702
}}</ref>

When xenon atoms are in the [[stationary state|ground energy state]], they repel each other and will not form a bond. When xenon atoms becomes energized, however, they can form an [[excimer]] (excited dimer) until the electrons return to the [[ground state]]. This entity is formed because the xenon atom tends to complete the outermost [[Electron shell|electronic shell]] by adding an electron from a neighboring xenon atom. The typical lifetime of a xenon excimer is 1–5&nbsp;nanoseconds, and the decay releases [[photon]]s with [[wavelength]]s of about 150 and 173&nbsp;[[Nanometre|nm]].<ref>{{cite book
| first     = William Thomas
| last      = Silfvast
| year      = 2004
| title     = Laser Fundamentals
| publisher = [[Cambridge University Press]]
| isbn      = 0-521-83345-0
| url       = https://books.google.com/books?id=x3VB2iwSaxsC&pg=RA1-PA152
}}</ref><ref>{{cite book
| first     = John G.
| last      = Webster
| date      = 1998
| title     = The Measurement, Instrumentation, and Sensors Handbook
| publisher = Springer
| isbn      = 3-540-64830-5
| url       = https://books.google.com/books?id=b7UuZzf9ivIC&pg=PT2427
}}</ref> Xenon can also form excimers with other elements, such as the [[halogen]]s [[bromine]], [[chlorine]], and [[fluorine]].<ref>{{cite book
| first     = Charles
| last      = McGhee
| date      = 1997
| author2   = Taylor, Hugh R.
| author3   = Gartry, David S.
| author4   = Trokel, Stephen L.
| title     = Excimer Lasers in Ophthalmology
| publisher = Informa Health Care
| isbn      = 1-85317-253-7
| url       = https://books.google.com/books?id=pg0bUc_GcVoC&pg=PA4
}}</ref>