Xenon tetrafluoride

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Xenon tetrafluoride
XeF 4 crystals. 1962. Xenon tetrafluoride.png
XeF
4 crystals. 1962.
Xenon-tetrafluoride-3D-balls.png
Xenon-tetrafluoride-3D-vdW.png
Names
IUPAC name
Xenon tetrafluoride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.858 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/F4Xe/c1-5(2,3)4 Yes check.svgY
    Key: RPSSQXXJRBEGEE-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/F4Xe/c1-5(2,3)4
    Key: RPSSQXXJRBEGEE-UHFFFAOYAW
  • F[Xe](F)(F)F
Properties
XeF
4
Molar mass 207.2836 g mol−1
AppearanceWhite solid
Density 4.040 g cm−3, solid
Melting point 117 °C (243 °F; 390 K) sublimes [1]
Reacts
Structure
D4h
square planar
0 D
Thermochemistry
Std molar
entropy (S⦵298)
146 J·mol−1·K−1 [2]
−251 kJ·mol−1 [2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Xenon tetrafluoride is a chemical compound with chemical formula XeF
4. It was the first discovered binary compound of a noble gas. [3] It is produced by the chemical reaction of xenon with fluorine: [4] [5]

Contents

Xe + 2 F
2 → XeF
4

This reaction is exothermic, releasing an energy of 251  kJ/mol. [3]

Its discovery in 1962 was inspired [4] by the discovery earlier in the same year by Neil Bartlett of the first xenon compound, XePtF6, which showed that it was possible for a xenon commpound to exist.

Xenon tetrafluoride is a colorless crystalline solid that sublimes at 117 °C. Its structure was determined by both NMR spectroscopy and X-ray crystallography in 1963. [6] [7] The structure is square planar, as has been confirmed by neutron diffraction studies. [8] According to VSEPR theory, in addition to four fluoride ligands, the xenon center has two lone pairs of electrons. These lone pairs are mutually trans.

Synthesis

The original synthesis of xenon tetrafluoride occurred through direct 1:5-molar-ratio combination of the elements in a nickel (Monel) vessel at 400 °C. [9] The nickel does not catalyze the reaction,[ citation needed ] but rather protects the container surfaces against fluoride corrosion. Controlling the process against impurities is difficult, as xenon difluoride  (XeF
2), tetrafluoride, and hexafluoride  (XeF
6) are all in chemical equilibrium, the difluoride favored at low temperatures and little fluorine and the hexafluoride favored at high temperatures and excess fluorine. [9] [10] Fractional sublimation (xenon tetrafluoride is particularly involatile) or other equilibria generally allow purification of the product mixture. [9]

The elements combine more selectively when γ- or UV-irradiated in a nickel container or dissolved in anhydrous hydrogen fluoride with catalytic oxygen. That reaction is believed selective because dioxygen difluoride at standard conditions is too weak an oxidant to generate xenon(VI) species. [9]

Alternatively, fluoroxenonium perfluorometallate salts pyrolyze to XeF4. [9]

Reactions

Xenon tetrafluoride hydrolyzes at low temperatures to form elemental xenon, oxygen, hydrofluoric acid, and aqueous xenon trioxide: [11]

It is used as a precursor for synthesis of all tetravalent Xe compounds. [9] Reaction with tetramethylammonium fluoride gives tetramethylammonium pentafluoroxenate, which contains the pentagonal XeF−
5 anion. The XeF−
5 anion is also formed by reaction with cesium fluoride: [12]

CsF + XeF
4 → CsXeF
5

Reaction with bismuth pentafluoride (BiF
5) forms the XeF+
3 cation: [13]

BiF
5 + XeF
4 → XeF3BiF6

The XeF+
3 cation in the salt XeF3Sb2F11 has been characterized by NMR spectroscopy. [14]

At 400 °C, XeF
4 reacts with xenon to form XeF
2 : [10]

XeF4 + Xe → 2 XeF2

The reaction of xenon tetrafluoride with platinum yields platinum tetrafluoride and xenon: [10]

XeF4 + Pt → PtF4 + Xe

Applications

Xenon tetrafluoride has few applications. It has been shown to degrade silicone rubber for analyzing trace metal impurities in the rubber. XeF
4 reacts with the silicone to form simple gaseous products, leaving a residue of metal impurities. [15]

References

  1. ↑ Holleman, Arnold F.; Wiberg, Egon (2001). Wiberg, Nils (ed.). Inorganic Chemistry. Translated by Eagleson, Mary; Brewer, William. Academic Press. p. 394. ISBN   0-12-352651-5.
  2. 1 2 Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin Company. p. A23. ISBN   978-0-618-94690-7.
  3. 1 2 Zumdahl (2007). Chemistry. Boston: Houghton Mifflin. p. 243. ISBN   978-0-618-52844-8.
  4. 1 2 Claassen, H. H.; Selig, H.; Malm, J. G. (1962). "Xenon Tetrafluoride". J. Am. Chem. Soc. 84 (18): 3593. doi:10.1021/ja00877a042.
  5. ↑ Chernick, C. L.; Claassen, H. H.; Fields, P. R.; Hyman, H. H.; Malm, J. G.; Manning, W. M.; Matheson, M. S.; Quarterman, L. A.; Schreiner, F.; Selig, H. H.; Sheft, I.; Siegel, S.; Sloth, E. N.; Stein, L.; Studier, M. H.; Weeks, J. L.; Zirin, M. H. (1962). "Fluorine Compounds of Xenon and Radon". Science. 138 (3537): 136–138. Bibcode:1962Sci...138..136C. doi:10.1126/science.138.3537.136. PMID   17818399. S2CID   10330125.
  6. ↑ Brown, Thomas H.; Whipple, E. B.; Verdier, Peter H. (1963). "Xenon Tetrafluoride: Fluorine-19 High-Resolution Magnetic Resonance Spectrum". Science. 140 (3563): 178. Bibcode:1963Sci...140..178B. doi:10.1126/science.140.3563.178. PMID   17819836. S2CID   35981023.
  7. ↑ Ibers, James A.; Hamilton, Walter C. (1963). "Xenon Tetrafluoride: Crystal Structure". Science. 139 (3550): 106–107. Bibcode:1963Sci...139..106I. doi:10.1126/science.139.3550.106. PMID   17798707. S2CID   42119788.
  8. ↑ Burns, John H.; Agron, P. A.; Levy, Henri A (1963). "Xenon Tetrafluoride Molecule and Its Thermal Motion: A Neutron Diffraction Study". Science. 139 (3560): 1208–1209. Bibcode:1963Sci...139.1208B. doi:10.1126/science.139.3560.1208. PMID   17757912. S2CID   35858682.
  9. 1 2 3 4 5 6 Haner, Jamie; Schrobilgen, Gary J. (2015). "The Chemistry of Xenon(IV)". Chem. Rev. 115 (2): 1255–1295. doi:10.1021/cr500427p. ISSN   0009-2665. PMID   25559700.
  10. 1 2 3 Bard, Allen J.; Parsons, Roger; Jordan, Joseph; International Union of Pure and Applied Chemistry (1985). Standard Potentials in Aqueous Solution. CRC Press. pp.  767–768. ISBN   0-8247-7291-1.
  11. ↑ Williamson; Koch, C. W. (Mar 1963). "Xenon Tetrafluoride: Reaction with Aqueous Solutions". Science. 139 (3559): 1046–1047. Bibcode:1963Sci...139.1046W. doi:10.1126/science.139.3559.1046. ISSN   0036-8075. PMID   17812981. S2CID   33320384.
  12. ↑ Harding, Charlie; Johnson, David Arthur; Janes, Rob (2002). Elements of the p Block. Molecular World. Vol. 9. Royal Society of Chemistry. p. 93. ISBN   0-85404-690-9.
  13. ↑ Suzuki, Hitomi; Matano, Yoshihiro (2001). Organobismuth chemistry. Elsevier. p. 8. ISBN   0-444-20528-4.
  14. ↑ Gillespie, R. J.; Landa, B.; Schrobilgen, G. J. (1971). "Trifluoroxenon(IV) µ-fluoro-bispentafluoroantimonate(V): the XeF+
    3     cation". Journal of the Chemical Society D: Chemical Communications (23): 1543–1544. doi:10.1039/C29710001543.
  15. ↑ Rigin, V.; Skvortsov, N. K.; Rigin, V. V. (March 1997). "Xenon tetrafluoride as a decomposition agent for silicone rubber for isolation and atomic emission spectrometric determination of trace metals". Analytica Chimica Acta. 340 (1–3): 1–3. Bibcode:1997AcAC..340....1R. doi:10.1016/S0003-2670(96)00563-6.
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