Noble gas compound

When the family of noble gases was first identified at the end of the nineteenth century, none of them were observed to form any compounds and so it was initially believed that they were all inert gases (as they were then known) which could not form compounds. With the development of atomic theory in the early twentieth century, their inertness was ascribed to a full valence shell of electrons which render them very chemically stable and nonreactive. All noble gases have full s and p outer electron shells (except helium, which has no p sublevel), and so do not form chemical compounds easily. Their high ionization energy and almost zero electron affinity explain their non-reactivity.

In 1933, Linus Pauling predicted that the heavier noble gases would be able to form compounds with fluorine and oxygen. Specifically, he predicted the existence of krypton hexafluoride ({{chem2|KrF6}}) and xenon hexafluoride ({{chem2|XeF6}}), speculated that {{chem2|XeF8}} might exist as an unstable compound, and suggested that xenic acid would form perxenate salts.{{cite journal

| title = The Formulas of Antimonic Acid and the Antimonates

| author = Pauling, Linus

| journal = J. Am. Chem. Soc.

| volume = 55

| issue = 5

| pages = 1895–1900

|date=June 1933

| doi = 10.1021/ja01332a016| bibcode = 1933JAChS..55.1895P

}}{{cite book

| last = Holloway

| first = John H.

| year = 1968

| title = Noble-Gas Chemistry

| publisher = Methuen

| location = London

| isbn = 0-416-03270-2

}} These predictions proved quite accurate, although subsequent predictions for {{chem2|XeF8}} indicated that it would be not only thermodynamically unstable, but kinetically unstable.{{cite journal

| last = Seppelt

| first = Konrad

|date=June 1979

| title = Recent developments in the Chemistry of Some Electronegative Elements

| journal = Accounts of Chemical Research

| volume = 12

| pages = 211–216

| doi = 10.1021/ar50138a004

| issue = 6

}} As of 2022, {{chem2|XeF8}} has not been made, although the octafluoroxenate(VI) anion (Nitrosonium octafluoroxenate(VI)) has been observed.

By 1960, no compound with a covalently bound noble gas atom had yet been synthesized.{{cite book

| last1 = Miessler

| first1 = Gary L.

| last2 = Tarr

| first2 = Donald A.

| title = Inorganic Chemistry

| edition = 2nd

| year = 1999

| page = 272

| publisher = Prentice Hall

| isbn = 0-13-841891-8

}} The first published report, in June 1962, of a noble gas compound was by Neil Bartlett, who noticed that the highly oxidising compound platinum hexafluoride ionised oxygen to dioxygenyl. As the ionisation energy of {{chem2|O2}} to {{chem2|O2+}} (1165 kJ mol⁻¹) is nearly equal to the ionisation energy of Xe to {{chem2|Xe+}} (1170 kJ mol⁻¹), he tried the reaction of Xe with {{chem2|PtF6}}. This yielded a crystalline product, xenon hexafluoroplatinate, whose formula was proposed to be {{chem2|Xe+[PtF6]-}}.{{cite journal | title = Xenon hexafluoroplatinate Xe⁺[PtF₆]⁻ | author = Bartlett, N. | journal = Proceedings of the Chemical Society of London | issue = 6 | page = 218 | year = 1962 | doi = 10.1039/PS9620000197}}

It was later shown that the compound is actually more complex, containing both {{chem2|[XeF]+[PtF5]-}} and {{chem2|[XeF]+[Pt2F11]-}}.{{cite journal | last = Graham | first = L. |author2=Graudejus, O. |author3=Jha N.K. |author4=Bartlett, N. | year = 2000 | title = Concerning the nature of XePtF₆ | journal = Coordination Chemistry Reviews | volume = 197 | pages = 321–334 | doi = 10.1016/S0010-8545(99)00190-3}} Nonetheless, this was the first real compound of any noble gas.

The first binary noble gas compounds were reported later in 1962. Bartlett synthesized xenon tetrafluoride ({{chem2|XeF4}}) by subjecting a mixture of xenon and fluorine to high temperature.{{cite journal |author1=Claassen, H. H. |author2=Selig, H. |author3=Malm, J. G. |title= Xenon Tetrafluoride |journal= J. Am. Chem. Soc. |volume= 84 |issue= 18 |page= 3593 |year= 1962 |doi= 10.1021/ja00877a042 |bibcode=1962JAChS..84.3593C }} Rudolf Hoppe, among other groups, synthesized xenon difluoride ({{chem2|XeF2}}) by the reaction of the elements.{{cite journal |doi=10.1002/anie.196205992 |author1=Hoppe, R. |author2=Daehne, W. |author3=Mattauch, H. |author4=Roedder, K. |title=Fluorination of Xenon |date=1962-11-01 |journal=Angew. Chem. Int. Ed. Engl. |volume=1 |page=599 |issue=11}}

Following the first successful synthesis of xenon compounds, synthesis of krypton difluoride ({{chem2|KrF2}}) was reported in 1963.{{cite journal|doi = 10.1016/S0010-8545(02)00202-3|title = The chemistry of krypton|year = 2002|last1 = Lehmann|first1 = J|journal = Coordination Chemistry Reviews|volume = 233–234|pages = 1–39}}

In this section, the non-radioactive noble gases are considered in decreasing order of atomic weight, which generally reflects the priority of their discovery, and the breadth of available information for these compounds. The radioactive elements radon and oganesson are harder to study and are considered at the end of the section.

{{main|Xenon compounds}}

After the initial 1962 studies on Xenon tetrafluoride and Xenon difluoride, xenon compounds that have been synthesized include other fluorides (xenon hexafluoride), oxyfluorides (Xenon oxydifluoride, Xenon oxytetrafluoride, Xenon dioxydifluoride, {{chem2|XeO3F2}}, {{chem2|XeO2F4}}) and oxides (xenon dioxide, xenon trioxide and xenon tetroxide). Xenon fluorides react with several other fluorides to form fluoroxenates, such as sodium octafluoroxenate(VI) ({{chem2|(Na+)2[XeF8](2-)}}),{{citation needed|date=January 2015}} and fluoroxenonium salts, such as trifluoroxenonium hexafluoroantimonate ({{chem2|[XeF3]+[SbF6]-}}).{{cite journal |title= [H(OXeF₂)_n][AsF₆] and [FXe^II(OXe^IVF₂)_n][AsF₆] (n = 1, 2): Examples of Xenon(IV) Hydroxide Fluoride and Oxide Fluoride Cations and the Crystal Structures of [F₃Xe—FH][Sb₂F₁₁] and [H₅F₄][SbF₆]·2[F₃Xe—FH][Sb₂F₁₁] |first1= David S. |last1= Brock |first2= Hélène P. A. |last2= Mercier |first3= Gary J. |last3= Schrobilgen |journal= Journal of the American Chemical Society |year= 2013 |volume= 135 |issue= 13 |pages= 5089–5104 |doi= 10.1021/ja312493j |pmid= 23398504 }}

In terms of other halide reactivity, short-lived excimers of noble gas halides such as xenon dichloride or XeCl are prepared in situ, and are used in the function of excimer lasers.{{Cite journal |last=Hutchinson |first=M. H. R. |date=1980|title=Excimers and excimer lasers|journal=Applied Physics |volume=21 |issue=2 |pages=95–114 |doi=10.1007/BF00900671 |bibcode=1980ApPhy..21...95H |s2cid=93808742 }}

Recently,{{when|date=January 2015}} xenon has been shown to produce a wide variety of compounds of the type {{chem2|XeO_{n}X2}} where n is 1, 2 or 3 and X is any electronegative group, such as {{chem2|CF3}}, Triflidic acid, {{chem2|N(SO2F)2}}, Bistriflimide, Teflate, {{chem2|O(IO2F2)}}, etc.; the range of compounds is impressive, similar to that seen with the neighbouring element iodine, running into the thousands and involving bonds between xenon and oxygen, nitrogen, carbon, boron and even gold, as well as perxenic acid, several halides, and complex ions.{{citation needed|date=January 2015}}

The compound {{chem2|[Xe2]+[Sb4F21]−}} contains a Xe–Xe bond, which is the longest element-element bond known (308.71 pm = 3.0871 Å).{{cite journal|doi = 10.1002/anie.199702731|title = The Xe₂⁺ Ion—Preparation and Structure|year = 1997|journal = Angewandte Chemie International Edition|volume = 36|pages = 273–274 | last1 = Drews | first1 = Thomas | last2 = Seppelt | first2 = Konrad|issue = 3}} Short-lived excimers of {{chem2|Xe2}} are reported to exist as a part of the function of excimer lasers.{{citation needed|date=January 2015}}

{{main|Krypton#Chemistry}}

Krypton gas reacts with fluorine gas under extreme forcing conditions, forming Krypton difluoride according to the following equation:

:{{chem2|Kr + F2 → KrF2}}

{{chem2|KrF2}} reacts with strong Lewis acids to form salts of the {{chem2|[KrF]+}} and {{chem2|[Kr2F3]+}} cations. The preparation of {{chem2|KrF4}} reported by Grosse in 1963, using the Claasen method, was subsequently shown to be a mistaken identification.{{Cite journal | doi = 10.1007/BF01375764 | title = Krypton difluoride | year = 1971 | last1 = Prusakov | first1 = V. N. | last2 = Sokolov | first2 = V. B. | journal = Soviet Atomic Energy | volume = 31 | issue = 3| pages = 990–999 | s2cid = 189775335 }}

Krypton compounds with other than Kr–F bonds (compounds with atoms other than fluorine) have also been described. {{chem2|KrF2}} reacts with {{chem2|B(OTeF5)3}} to produce the unstable compound, {{chem2|Kr(OTeF5)2}}, with a krypton-oxygen bond. A krypton-nitrogen bond is found in the cation {{chem2|[H\sC\tN\sKr\sF]+}}, produced by the reaction of {{chem2|KrF2}} with {{chem2|[H\sC\tN\sH]+[AsF6]−}} below −50 °C.{{cite book| title = Advances in Inorganic Chemistry| url = https://archive.org/details/isbn_0120236451| url-access = limited|author = John H. Holloway|author2 = Eric G. Hope|editor = A. G. Sykes| publisher = Academic Press|date = 1998| isbn = 0-12-023646-X|page = [https://archive.org/details/isbn_0120236451/page/n59 57]}}

{{main|Argon compounds}}

{{expand section|small=no|date=January 2015}}

The discovery of HArF was announced in 2000.{{cite journal |author=Khriachtchev, L., Pettersson, M., Runeberg, N., Lundell, J., Räsänen, M. |title= A stable argon compound |journal= Nature |volume= 406 |pages= 874–876 |year= 2000 |doi= 10.1038/35022551 |pmid=10972285 |issue=6798 |bibcode= 2000Natur.406..874K |s2cid= 4382128 }}{{cite journal|last1=Bochenkova|first1=Anastasia V.|last2=Bochenkov|first2=Vladimir E.|last3=Khriachtchev|first3=Leonid|title=HArF in Solid Argon Revisited: Transition from Unstable to Stable Configuration|journal=The Journal of Physical Chemistry A|date=2 July 2009|volume=113|issue=26|pages=7654–7659|doi=10.1021/jp810457h|pmid=19243121|bibcode=2009JPCA..113.7654B}} The compound can exist in low temperature argon matrices for experimental studies, and it has also been studied computationally. Argon hydride ion {{chem2|[ArH]+}} was obtained in the 1970s.{{cite journal|last1=Wyatt|first1=J. R.|last2=Strattan|first2=L. W.|last3=Snyder|first3=S. C.|last4=Hierl|first4=P. M.|title=Chemical accelerator studies of reaction dynamics: {{chem|Ar|+}} + {{chem|CH|4}} → {{chem|ArH|+}} + {{chem|CH|3}}|journal=The Journal of Chemical Physics|date=1975|volume=62|issue=7|page=2555|doi=10.1063/1.430836|bibcode=1975JChPh..62.2555W|url=https://kuscholarworks.ku.edu/bitstream/1808/16098/1/HierlP_JCP_1975%2862%292555.pdf|hdl=1808/16098|hdl-access=free}}

This molecular ion has also been identified in the Crab nebula, based on the frequency of its light emissions.{{cite journal|last1=Barlow|first1=M. J.|last2=Swinyard|first2=B. M.|last3=Owen|first3=P. J.|last4=Cernicharo|first4=J.|last5=Gomez|first5=H. L.|last6=Ivison|first6=R. J.|last7=Krause|first7=O.|last8=Lim|first8=T. L.|last9=Matsuura|first9=M.|last10=Miller|first10=S.|last11=Olofsson|first11=G.|last12=Polehampton|first12=E. T.|title=Detection of a Noble Gas Molecular Ion, {{chem|36|ArH|+}}, in the Crab Nebula|journal=Science|date=12 December 2013|volume=342|issue=6164|pages=1343–1345|doi=10.1126/science.1243582|pmid=24337290|arxiv=1312.4843|bibcode=2013Sci...342.1343B|s2cid=37578581}}

There is a possibility that a solid salt of {{chem2|[ArF]+}} could be prepared with Hexafluoroantimonate or hexafluoroaurate anions.{{cite journal|last1=Frenking|first1=Gernot|last2=Koch|first2=Wolfram|last3=Deakyne|first3=Carol A.|last4=Liebman|first4=Joel F.|last5=Bartlett|first5=Neil|title=The ArF⁺ cation. Is it stable enough to be isolated in a salt?|journal=Journal of the American Chemical Society|date=January 1989|volume=111|issue=1|pages=31–33|doi=10.1021/ja00183a005|bibcode=1989JAChS.111...31F }}{{Cite book|last1=Selig|first1=Henry|last2=Holloway|first2=John H.|title=Cationic and anionic complexes of the noble gases|date=27 May 2005|volume=124|pages=33–90|doi=10.1007/3-540-13534-0_2|series=Topics in Current Chemistry|isbn=978-3-540-13534-0|s2cid=91636049 }}

{{anchor|Helium compounds|Neon compounds}}

{{main|Helium compounds|Neon compounds}}

The ions, {{chem2|Ne+}}, {{chem2|[NeAr]+}}, {{chem2|[NeH]+}}, and {{chem2|[HeNe]+}} are known from optical and mass spectrometric studies. Neon also forms an unstable hydrate.{{Cite web|url=https://periodic.lanl.gov/10.shtml|title=Periodic Table of Elements: Los Alamos National Laboratory|website=periodic.lanl.gov|access-date=2019-12-13}} There is some empirical and theoretical evidence for a few metastable helium compounds which may exist at very low temperatures or extreme pressures. The stable cation helium hydride ion was reported in 1925,{{cite journal |last1=Hogness |first1=T.R. |last2=Lunn |first2=E.G. |year=1925 |title=The Ionization of Hydrogen by Electron Impact as Interpreted by Positive Ray Analysis |url=https://journals.aps.org/pr/abstract/10.1103/PhysRev.26.44 |journal=Phys. Rev. Lett. |publisher=The American Physical Society |volume=26 |issue=1 |pages=44–55 |doi=10.1103/PhysRev.26.44 |access-date=15 December 2013|bibcode=1925PhRv...26...44H |url-access=subscription }} but was not considered a true compound since it is not neutral and cannot be isolated. In 2016 scientists created the helium compound disodium helide ({{chem2|Na2He}}) which was the first helium compound discovered.{{Cite web|url=https://www.sciencealert.com/forget-what-you-learned-scientists-might-have-just-created-a-stable-helium-compound|title=Forget What You've Learned – Scientists Just Created a Stable Helium Compound|last=Crew|first=Bec|website=ScienceAlert|date=7 February 2017|access-date=2019-12-13}}

{{anchor|Radon compounds|Oganesson compounds}}

{{main|Radon#Chemical properties|Oganesson#Predicted compounds}}

Radon is not chemically inert, but its short half-life (3.8 days for ²²²Rn) and the high energy of its radioactivity make it difficult to investigate its only fluoride ({{chem2|RnF2}}), its reported oxide ({{chem2|RnO3}}), and their reaction products.{{cite journal | author = Kenneth S. Pitzer | year = 1975 | journal = J. Chem. Soc., Chem. Commun. | pages = 760b – 761 | title = Fluorides of radon and element 118 | doi = 10.1039/C3975000760b | issue = 18| url = https://escholarship.org/content/qt8xz4g1ff/qt8xz4g1ff.pdf?t=p2at3t }}

All known oganesson isotopes have even shorter half-lives in the millisecond range and no compounds are known yet,{{cite book |chapter=Synthesis of Superheavy Elements |last1=Moody |first1=Ken |editor1-first=Matthias |editor1-last=Schädel |editor2-first=Dawn |editor2-last=Shaughnessy |title=The Chemistry of Superheavy Elements |publisher=Springer Science & Business Media |edition=2nd |pages=24–8 |isbn=9783642374661|date=2013-11-30 }} although some have been predicted theoretically. It is expected to be even more reactive than radon, more like a normal element than a noble gas in its chemistry.{{Cite journal|last1=Fricke |first1=Burkhard |year=1975 |title=Superheavy elements: a prediction of their chemical and physical properties |journal=Recent Impact of Physics on Inorganic Chemistry |volume=21 |pages=[https://archive.org/details/recentimpactofph0000unse/page/89 89–144] |doi=10.1007/BFb0116498 |url=https://archive.org/details/recentimpactofph0000unse/page/89 |access-date=4 October 2013 |series=Structure and Bonding |isbn=978-3-540-07109-9 }}

File:Krypton hydride crystal.jpg. Ruby was added for pressure measurement.]]

File:Krypton hydride structure.png

Prior to 1962, the only isolated compounds of noble gases were clathrates (including clathrate hydrates); other compounds such as coordination compounds were observed only by spectroscopic means. Clathrates (also known as cage compounds) are compounds of noble gases in which they are trapped within cavities of crystal lattices of certain organic and inorganic substances. Ar, Kr, Xe and Ne{{cite journal|doi=10.1038/s43246-023-00378-z |title=Neon encapsulation by a hydroquinone organic crystalline clathrate under ambient conditions |date=2023 |last1=Lim |first1=Sol Geo |last2=Lee |first2=Jong-Won |last3=Fujihisa |first3=Hiroshi |last4=Oh |first4=Chang Yeop |last5=Jang |first5=Jiyeong |last6=Moon |first6=Dohyun |last7=Takeya |first7=Satoshi |last8=Muraoka |first8=Michihiro |last9=Yamamoto |first9=Yoshitaka |last10=Yoon |first10=Ji-Ho |journal=Communications Materials |volume=4 |issue=1 |page=51 |bibcode=2023CoMat...4...51L |s2cid=259583357 |doi-access=free }} can form clathrates with crystalline hydroquinone. Kr and Xe can appear as guests in crystals of melanophlogite.{{Cite journal |last1=Gunawardane |first1=R. P. |last2=Gies |first2=H. |last3=Liebau |first3=F. |date=March 1987 |title=Studies on Clathrasils. X. The effect of "help gases" on the formation and stability of clathrasils |journal=Zeitschrift für anorganische und allgemeine Chemie |language=de |volume=546 |issue=3 |pages=189–198 |doi=10.1002/zaac.19875460321 }}

Helium-nitrogen ({{chem2|He(N2)11}}) crystals have been grown at room temperature at pressures ca. 10 GPa in a diamond anvil cell.{{cite journal|doi=10.1038/358046a0|title=A high-pressure van der Waals compound in solid nitrogen-helium mixtures|journal=Nature|volume=358|issue=6381|pages=46–48|year=1992|last1=Vos|first1=W. L.|last2=Finger|first2=L. W.|last3=Hemley|first3=R. J.|last4=Hu|first4=J. Z.|last5=Mao|first5=H. K.|last6=Schouten|first6=J. A.|bibcode=1992Natur.358...46V|s2cid=4313676}} Solid argon-hydrogen clathrate ({{chem2|Ar(H2)2}}) has the same crystal structure as the {{chem2|MgZn2}} Laves phase. It forms at pressures between 4.3 and 220 GPa, though Raman measurements suggest that the {{chem2|H2}} molecules in {{chem2|Ar(H2)2}} dissociate above 175 GPa. A similar {{chem2|Kr(H2)4}} solid forms at pressures above 5 GPa. It has a face-centered cubic structure where krypton octahedra are surrounded by randomly oriented hydrogen molecules. Meanwhile, in solid {{chem2|Xe(H2)8}} xenon atoms form dimers inside solid hydrogen.{{cite journal|doi=10.1038/srep04989|title=New high-pressure van der Waals compound Kr(H₂)₄ discovered in the krypton-hydrogen binary system|journal=Scientific Reports|volume=4|year=2014|last1=Kleppe|first1=Annette K.|last2=Amboage|first2=Mónica|last3=Jephcoat|first3=Andrew P.|page=4989|bibcode=2014NatSR...4.4989K|doi-access=free}}

Coordination compounds such as {{chem2|Ar*BF3}} have been postulated to exist at low temperatures, but have never been confirmed.{{citation needed|date=January 2015}}

Xenon is known to function as a metal ligand. In addition to the charged [AuXe₄]²⁺, xenon, krypton, and argon all reversibly bind to gaseous M(CO)₅, where M=Cr, Mo, or W. P-block metals also bind noble gases: XeBeO has been observed spectroscopically and both XeBeS and FXeBO are predicted stable.{{cite journal|via=CiteSeerX|at=p. 1638 and fn. 53–55|journal=Chemical Society Reviews|volume=36|issue=10|date=Oct 2007|title=Atypical compounds of gases, which have been called 'noble'|first=Wojciech|last=Grochala|orig-date=12 April 2007|doi=10.1039/b702109g|publisher=Royal Society of Chemistry|pmid=17721587 }}

Also, compounds such as {{chem2|WHe2}} and {{chem2|HgHe2}} were reported to have been formed by electron bombardment, but recent research has shown that these are probably the result of He being adsorbed on the surface of the metal; therefore, these compounds cannot truly be considered chemical compounds.{{citation needed|date=January 2015}}

Hydrates are formed by compressing noble gases in water, where it is believed that the water molecule, a strong dipole, induces a weak dipole in the noble gas atoms, resulting in dipole-dipole interaction. Heavier atoms are more influenced than smaller ones, hence {{chem2|Xe*5.75H2O}} was reported to have been the most stable hydrate;{{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

|date=1961|pages=15–21|pmid=13733483

|last=Pauling|first=L.|bibcode = 1961Sci...134...15P }} Reprinted as {{cite book

|pages=1328–1334|title=Linus Pauling: Selected Scientific Papers|volume=2|editor=Pauling, Linus|editor2=Kamb, Barclay

|place=River Edge, New Jersey|publisher=World Scientific

|date=2001|isbn=981-02-2940-2|url=https://books.google.com/books?id=2QduA19d_X8C&pg=PA1329}} it has a melting point of 24 °C.{{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}} The deuterated version of this hydrate has also been produced.{{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=10623–10630|doi=10.1021/jp001313j|bibcode=2000JPCA..10410623I}}

{{main|endohedral fullerene#Non-metal doped fullerenes|l1=Non-metal doped fullerenes}}

Image:Endohedral fullerene.png Noble gases can also form endohedral fullerene compounds where the noble gas atom is trapped inside a fullerene molecule. In 1993, it was discovered that when {{chem2|C60}} is exposed to a pressure of around 3 bar of He or Ne, the complexes {{chem2|He@C60}} and {{chem2|Ne@C60}} are formed.{{cite journal|title=Stable compounds of helium and neon. He@C60 and Ne@C60|author1=Saunders, M. |author2=Jiménez-Vázquez, H. A. |author3=Cross, R. J. |author4=Poreda, R. J. |name-list-style=amp |journal=Science|year=1993|volume=259|pages=1428–1430|doi=10.1126/science.259.5100.1428|pmid=17801275|issue=5100|bibcode = 1993Sci...259.1428S |s2cid=41794612 }} Under these conditions, only about one out of every 650,000 {{chem2|C60}} cages was doped with a helium atom; with higher pressures (3000 bar), it is possible to achieve a yield of up to 0.1%. Endohedral complexes with argon, krypton and xenon have also been obtained, as well as numerous adducts of {{chem2|He@C60}}.{{cite journal|title=Incorporation of helium, neon, argon, krypton, and xenon into fullerenes using high pressure|author1=Saunders, Martin |author2=Jimenez-Vazquez, Hugo A. |author3=Cross, R. James |author4=Mroczkowski, Stanley |author5=Gross, Michael L. |author6=Giblin, Daryl E. |author7=Poreda, Robert J. |name-list-style=amp |journal=J. Am. Chem. Soc.|year=1994|volume=116|issue=5|pages=2193–2194|doi=10.1021/ja00084a089|bibcode=1994JAChS.116.2193S }}

Most applications of noble gas compounds are either as oxidising agents or as a means to store noble gases in a dense form. Xenic acid is a valuable oxidising agent because it has no potential for introducing impurities—xenon is simply liberated as a gas—and so is rivalled only by ozone in this regard. The perxenates are even more powerful oxidizing agents.{{citation needed|date=January 2015}} Xenon-based oxidants have also been used for synthesizing carbocations stable at room temperature, in sulfuryl chloride fluoride solution.{{cite journal | last2 = Moran | last3 = Schrobilgen | last4 = Steinberg | last5 = Suontamo | first1 = H. P. A.|last1 = Mercier | first2 = M. D. | first3 = G. J. | first4 = C. | first5 = R. J. | year = 2004 | title = The Syntheses of Carbocations by Use of the Noble-Gas Oxidant, {{chem|[XeOTeF|5|][Sb(OTeF|5|)|6|]}}: The Syntheses and Characterization of the {{chem|CX|3|+}} (X = Cl, Br, {{chem|OTeF|5}}) and {{chem|CBr(OTeF|5|)|2|+}} Cations and Theoretical Studies of {{chem|CX|3|+}} and {{chem|BX|3}} (X = F, Cl, Br, I, {{chem|OTeF|5}}) | journal = J. Am. Chem. Soc. | pmid = 15113225 | volume = 126 | issue = 17 | pages = 5533–5548 | doi = 10.1021/ja030649e }}{{primary source inline|date=January 2015}}

Stable salts of xenon containing very high proportions of fluorine by weight (such as tetrafluoroammonium heptafluoroxenate(VI), {{chem2|[NF4][XeF7]}}, and the related tetrafluoroammonium octafluoroxenate(VI) {{chem2|[NF4]2[XeF8]}}), have been developed as highly energetic oxidisers for use as propellants in rocketry.{{cite journal | last1 = Christe | first1 = KO | last2 = Wilson | first2 = WW | date = Dec 1982 | title = Perfluoroammonium and alkali-metal salts of the heptafluoroxenate(VI) and octafluoroxenate(VI) anions | journal = Inorganic Chemistry | volume = 21 | issue = 12| pages = 4113–4117 | doi = 10.1021/ic00142a001 }}{{primary source inline|date=January 2015}} Christe, Karl O., Wilson, William W. Perfluoroammonium salt of heptafluoroxenon anion. {{US Patent|4428913}}, June 24, 1982

Xenon fluorides are good fluorinating agents.{{cite journal |title= A Quantitative Scale for the Oxidizing Strength of Oxidative Fluorinators |first1= Karl O. |last1= Christe |first2= David A. |last2= Dixon |journal= Journal of the American Chemical Society |year= 1992 |volume= 114 |issue= 8 |pages= 2978–2985 |doi= 10.1021/ja00034a033 |bibcode= 1992JAChS.114.2978C }}

Clathrates have been used for separation of He and Ne from Ar, Kr, and Xe, and also for the transportation of Ar, Kr, and Xe.{{citation needed|date=January 2015}} (For instance, radioactive isotopes of krypton and xenon are difficult to store and dispose, and compounds of these elements may be more easily handled than the gaseous forms.) In addition, clathrates of radioisotopes may provide suitable formulations for experiments requiring sources of particular types of radiation; hence. ⁸⁵Kr clathrate provides a safe source of beta particles, while ¹³³Xe clathrate provides a useful source of gamma rays.{{cite journal |title= Clathrate compounds of quinol |last= Bhatnagar |first= Vijay M. |journal= Defence Science Journal, Supplement |year= 1963 |volume= 13 |issue= 4 |pages= 57–66 }}

{{reflist}}

• {{cite journal | last1 = Khriachtchev | first1 = Leonid | last2 = Räsänen | first2 = Markku | last3 = Gerber | first3 = R. Benny | title = Noble-Gas Hydrides: New Chemistry at Low Temperatures | journal = Accounts of Chemical Research | volume = 42 | issue = 1 | pages = 183–91 | year = 2009 | pmid = 18720951 | doi = 10.1021/ar800110q}}

{{Noble gas compounds}}

{{Chemical compounds by element}}

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