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To prevent decomposition , the xenon tetroxide thus formed is quickly cooled to form a pale @-@ yellow solid . It explodes above βˆ’ 35 @.@ 9 Β° C into xenon and oxygen gas .
A number of xenon oxyfluorides are known , including XeOF
2 , XeOF
4 , XeO
2F
2 , and XeO
3F
2 . XeOF
2 is formed by the reaction of OF
2 with xenon gas at low temperatures . It may also be obtained by the partial hydrolysis of XeF
4 . It disproportionates at βˆ’ 20 Β° C into XeF
2 and XeO
2F
2 . XeOF
4 is formed by the partial hydrolysis of XeF
6 , or the reaction of XeF
6 with sodium perxenate , Na
4XeO
6 . The latter reaction also produces a small amount of XeO
3F
2 . XeOF
4 reacts with CsF to form the XeOF βˆ’
5 anion , while XeOF3 reacts with the alkali metal fluorides KF , RbF and CsF to form the XeOF βˆ’
4 anion .
= = = Other compounds = = =
Recently , there has been an interest in xenon compounds where xenon is directly bonded to a less electronegative element than fluorine or oxygen , particularly carbon . Electron @-@ withdrawing groups , such as groups with fluorine substitution , are necessary to stabilize these compounds . Numerous such compounds have been characterized , including :
C
6F
5 – Xe + – N ≑ C – CH
3 , where C6F5 is the pentafluorophenyl group .
[ C
6F
5 ]
2Xe
C
6F
5 – Xe – X , where X is CN , F , or Cl .
R – C ≑ C – Xe + , where R is C
2F βˆ’
5 or tert @-@ butyl .
C
6F
5 – XeF +
2
( C
6F
5Xe )
2Cl +
Other compounds containing xenon bonded to a less electronegative element include F – Xe – N ( SO
2F )
2 and F – Xe – BF
2 . The latter is synthesized from dioxygenyl tetrafluoroborate , O
2BF
4 , at βˆ’ 100 Β° C.
An unusual ion containing xenon is the tetraxenonogold ( II ) cation , AuXe2 +
4 , which contains Xe – Au bonds . This ion occurs in the compound AuXe
4 ( Sb
2F
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 .
The compound Xe
2Sb
2F
11 contains a Xe – Xe bond , the longest element @-@ element bond known ( 308 @.@ 71 pm = 3 @.@ 0871 Γ… ) .
In 1995 , M. RΓ€sΓ€nen 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 . In 2008 , Khriachtchev et al. reported the preparation of HXeOXeH by the photolysis of water within a cryogenic xenon matrix . Deuterated molecules , HXeOD and DXeOH , have also been produced .
= = = Clathrates and excimers = = =
In addition to compounds where xenon forms a chemical bond , xenon can form clathrates β€” substances where xenon atoms or pairs are trapped by the crystalline lattice of another compound . One example is xenon hydrate ( Xe β€’ 5 @.@ 75 H2O ) , where xenon atoms occupy vacancies in a lattice of water molecules . This clathrate has a melting point of 24 Β° C. The deuterated version of this hydrate has also been produced . Another example is Xe hydride ( Xe ( H2 ) 8 ) , in which xenon pairs ( dimers ) are trapped inside solid hydrogen . Such clathrate hydrates can occur naturally under conditions of high pressure , such as in Lake Vostok underneath the Antarctic ice sheet . Clathrate formation can be used to fractionally distill xenon , argon and krypton .
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 ( NMR ) 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 .
When xenon atoms are at their 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 fill its outermost electronic shell , and can briefly do this by adding an electron from a neighboring xenon atom . The typical lifetime of a xenon excimer is 1 – 5 ns , and the decay releases photons with wavelengths of about 150 and 173 nm . Xenon can also form excimers with other elements , such as the halogens bromine , chlorine and fluorine .
= = Applications = =
Although xenon is rare and relatively expensive to extract from the Earth 's atmosphere , it has a number of applications .
= = = Illumination and optics = = =
= = = = Gas @-@ discharge lamps = = = =
Xenon is used in light @-@ emitting devices called xenon flash lamps , which are used in photographic flashes and stroboscopic lamps ; to excite the active medium in lasers which then generate coherent light ; and , occasionally , in bactericidal lamps . The first solid @-@ state laser , invented in 1960 , was pumped by a xenon flash lamp , and lasers used to power inertial confinement fusion are also pumped by xenon flash lamps .
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 . They are employed in typical 35mm , IMAX and the new digital projectors film projection systems , automotive HID headlights , high @-@ end " tactical " flashlights 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 .
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 .
= = = = Lasers = = = =
In 1962 , a group of researchers at Bell Laboratories discovered laser action in xenon , and later found that the laser gain was improved by adding helium to the lasing medium . 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 . Xenon chloride and xenon fluoride have also been used in excimer ( or , more accurately , exciplex ) lasers . The xenon chloride excimer laser has been employed , for example , in certain dermatological uses .
= = = Medical = = =
= = = = Anesthesia = = = =
Xenon has been used as a general anesthetic . Although it is expensive , anesthesia machines that can deliver xenon are about to appear on the European market , because advances in recovery and recycling of xenon have made it economically viable .
Xenon interacts with many different receptors and ion channels and like many theoretically multi @-@ modal inhalation anesthetics these interactions are likely complementary . Xenon is a high @-@ affinity glycine @-@ site NMDA receptor antagonist . However , xenon distinguishes itself from other clinically used NMDA receptor antagonists in its lack of neurotoxicity and its ability to inhibit the neurotoxicity of ketamine and nitrous oxide . Unlike ketamine and nitrous oxide , xenon does not stimulate a dopamine efflux in the nucleus accumbens . Like nitrous oxide and cyclopropane , xenon activates the two @-@ pore domain potassium channel TREK @-@ 1 . A related channel TASK @-@ 3 also implicated in inhalational anesthetic actions is insensitive to xenon . Xenon inhibits nicotinic acetylcholine Ξ±4Ξ²2 receptors which contribute to spinally mediated analgesia . Xenon is an effective inhibitor of plasma membrane Ca2 + ATPase . Xenon inhibits Ca2 + ATPase by binding to a hydrophobic pore within the enzyme and preventing the enzyme from assuming active conformations .
Xenon is a competitive inhibitor of the serotonin 5 @-@ HT3 receptor . While neither anesthetic nor antinociceptive this activity reduces anesthesia @-@ emergent nausea and vomiting .