Chlorine trifluoride oxide

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Chlorine trifluoride oxide
Chlorine-trifluoride-oxide-3D-vdW.png
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Names
IUPAC name
trifluoro(oxo)-λ5-chlorane
Other names
Chlorosyl trifluoride
Identifiers
3D model (JSmol)
PubChem CID
  • InChI=1S/ClF3O/c2-1(3,4)5
    Key: QPKQQPNQDSQNHS-UHFFFAOYSA-N
  • O=Cl(F)(F)F
Properties
ClOF3
Molar mass 108.44 g·mol−1
AppearanceColorless liquid
Density 1.865 g/cm3
Melting point −42 °C (−44 °F; 231 K)
Boiling point 29 °C (84 °F; 302 K)
Structure
monoclinic
C2/m
a = 9.826, b = 12.295, c = 4.901
α = 90°, β = 90.338°, γ = 90° [2]
592.1
8
Hazards
GHS labelling:
GHS-pictogram-rondflam.svg GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-pollu.svg
Danger
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chlorine oxide trifluoride or chlorine trifluoride oxide is a corrosive colorless liquid molecular compound with formula Cl O F 3. It was developed secretly as a rocket fuel oxidiser.

Contents

Production

Chlorine oxide trifluoride was originally made at Rocketdyne [3] by treating dichlorine monoxide with fluorine. Other substances that could react with fluorine to make it includes sodium chlorite NaClO2, and chlorine nitrate Cl−O−NO2. The first published production method was a reaction of dichlorine monoxide with oxygen difluoride OF2. Yet other production methods are reactions between ClO2F or ClO3F and chlorine fluorides. [4] A safer approach is the use chlorine nitrate with fluorine.

Reactions

As a Lewis base it can lose a fluoride ion to Lewis acids, yielding the difluorooxochloronium(V) cation [ClOF2]+. [5] Compounds with this include: [ClOF2]+[BF4], [ClOF2]+[PF6], [ClOF2]+[AsF6], [ClOF2]+[SbF6], [ClOF2]+[BiF6], [ClOF2]+[VF6], [ClOF2]+[NbF6], [ClOF2]+[TaF6], [ClOF2]+[UF6], ([ClOF2]+)2[SiF6]2−, [ClOF2]+[MoOF5], [ClOF2]+[Mo2O4F9], [4] [ClOF2]+[PtF6]. [6]

Functioning as a Lewis acid, it can gain a fluoride ion from a strong base to yield a tetrafluorooxochlorate(V) anion ClOF4. [7] These include K+[ClOF4] (potassium tetrafluorooxochlorate(V)), Rb+[ClOF4] (rubidium tetrafluorooxochlorate(V)), and Cs+[ClOF4] (caesium tetrafluorooxochlorate(V)). These three salts are white crystalline solids. [4] [8] This allows purification of ClOF3, as at room temperature a solid complex is formed, but this decomposes between 50 and 70 °C. Other likely impurities either will not react with alkali fluoride, or if they do will not easily decompose. [3]

Chlorine trifluoride oxide fluoridates various materials such as chlorine monoxide, chlorine, glass or quartz. [3]

ClOF3 + Cl2O → 2 ClF + ClO2F [6]
2 ClOF3 + 2 Cl2 → 6 ClF + O2 at 200 °C [6]

Chlorine trifluoride oxide adds to chlorine fluorosulfate:

ClOF3 + 2 ClOSO2F → S2O5F2 + FClO2 + 2 ClF.

The reaction also produces SO2F2. [3]

Chlorine trifluoride oxide can fluoridate and add oxygen in the same reaction, reacting with molybdenum pentafluoride, silicon tetrafluoride, tetrafluorohydrazine (over 100 °C), HNF2, and F2NCOF. From HNF2 the main result was NF3O. From MoF5, the results were MoF6 and MoOF4. [3]

It reacts explosively with hydrocarbons. [3] With small amounts of water, ClO2F is formed along with HF. [3]

Over 280 °C ClOF3 decomposes to oxygen and chlorine trifluoride. [3]

Properties

The boiling point of chlorine trifluoride oxide is 29 °C. [9]

The shape of the molecule is a trigonal bipyramid, with two fluorine atoms at the top and bottom (apex) (Fa) and an electron pair, oxygen and fluorine (Fe) on the equator. [7] The Cl=O bond length is 1.405 Å, Cl-Fe 1.603 Å, other Cl-Fa 1.713 Å, ∠FeClO=109° ∠FaClO=95°, ∠FaClFe=88°. The molecule is polarised, Cl has a +1.76 charge, O has −0.53, equatorial F has −0.31 and apex F has −0.46. The total dipole moment is 1.74 D. [10]

References

  1. Urben, Peter (2017). Bretherick's Handbook of Reactive Chemical Hazards. Elsevier. p. 784. ISBN   9780081010594.
  2. Ellern, Arkady; Boatz, Jerry A.; Christe, Karl O.; Drews, Thomas; Seppelt, Konrad (September 2002). "The Crystal Structures of ClF3O, BrF3O, and [NO]+[BrF4O]". Zeitschrift für anorganische und allgemeine Chemie. 628 (9–10): 1991–1999. doi:10.1002/1521-3749(200209)628:9/10<1991::AID-ZAAC1991>3.0.CO;2-1.
  3. 1 2 3 4 5 6 7 8 Advances in Inorganic Chemistry and Radiochemistry. Academic Press. 1976. pp. 331–333. ISBN   9780080578675.
  4. 1 2 3 Holloway, John H.; Laycock, David (1983). Advances in Inorganic Chemistry. Academic Press. pp. 178–179. ISBN   9780080578767.
  5. Christe, Karl O.; Curtis, E. C.; Schack, Carl J. (September 1972). "Chlorine trifluoride oxide. VII. Difluorooxychloronium(V) cation, ClF2O+. Vibrational spectrum and force constants". Inorganic Chemistry. 11 (9): 2212–2215. doi:10.1021/ic50115a046.
  6. 1 2 3 Schack, Carl J.; Lindahl, C. B.; Pilipovich, Donald.; Christe, Karl O. (September 1972). "Chlorine trifluoride oxide. IV. Reaction chemistry". Inorganic Chemistry. 11 (9): 2201–2205. doi:10.1021/ic50115a043.
  7. 1 2 Christe, K.O.; Schack, C.J. (1976). Chlorine Oxyfluorides. Advances in Inorganic Chemistry and Radiochemistry. Vol. 18. pp. 319–398. doi:10.1016/S0065-2792(08)60033-3. ISBN   9780120236183.
  8. Christe, Karl O.; Schack, Carl J.; Pilipovich, Donald.; Christe, Karl O. (September 1972). "Chlorine trifluoride oxide. V. Complex formation with Lewis acids and bases". Inorganic Chemistry. 11 (9): 2205–2208. doi:10.1021/ic50115a044.
  9. Pilipovich, Donald.; Lindahl, C. B.; Schack, Carl J.; Wilson, R. D.; Christe, Karl O. (September 1972). "Chlorine trifluoride oxide. I. Preparation and properties". Inorganic Chemistry. 11 (9): 2189–2192. doi:10.1021/ic50115a040.
  10. Oberhammer, Heinz.; Christe, Karl O. (January 1982). "Gas-phase structure of chlorine trifluoride oxide, ClF3O". Inorganic Chemistry. 21 (1): 273–275. doi:10.1021/ic00131a050.