Pentafluorosulfur hypofluorite

Pentafluorosulfur hypofluorite is an oxyfluoride of sulfur in the +6 oxidation state, with a fluorine atom attached to oxygen. The formula is SOF6. In standard conditions it is a gas.[1]

Pentafluorosulfur hypofluorite
Names
IUPAC name
Pentafluorosulfur hypofluorite
Other names
  • Sulfur fluoride hypofluorite
  • Thionyl fluoride hypofluorite
Identifiers
3D model (JSmol)
  • InChI=1S/F6OS/c1-7-8(2,3,4,5)6
    Key: DGQBNDRZRZYTER-UHFFFAOYSA-N
  • S(F)(F)(F)(F)(F)OF
Properties
SOF6
Appearance Colorless gas
Density 1.947 at -47.2 °C[1]
Melting point −86 °C (−123 °F; 187 K)[1]
Boiling point −35.1 °C (−31.2 °F; 238.1 K)[1]
Reacts with water
log P 6.03633-420.35/T-78360/T²[1]
Related compounds
Related oxohalides
Thionyl tetrafluoride
Thionyl fluoride,
sulfonyl fluoride
Related compounds
sulfuryl fluoride
sulfur hexafluoride
pentafluorooxosulfuric acid
bis-(pentafluorosulfur) oxide
bis-(pentafluorosulfur) peroxide
bis-(pentafluorosulfur) trioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Synthesis

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SOF6 can be made by reacting thionyl fluoride with fluorine at 200 °C with a silver difluoride catalyst.[2]

SOF2 + 2F2 → SOF6 (+ some SOF4)

Properties

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The molecular shape has five fluorine and one oxygen atom arranged around a sulfur atom in an octahedral arrangement. Another fluorine atom is attached to the oxygen in almost a straight line with the S-O connection. So the molecular formula can also be written as SF5OF. The average S-F distance is 1.53 Å. The angles ∠FSF and ∠FSO are 90°.[2]

The 19F nuclear magnetic resonance spectrum of SOF6 compared to SF6 has a -131.5 ppm shift for the hypofluorite fluorine, and 1.75 ppm for the opposite F. The other four fluorine atoms have a shift of 3.64 ppm. Spin coupling of o-F to SF4 is 17.4 Hz, between SF4 and opposite (apex) SF 155 Hz, and between apex and hypofluorite it is 0.0.[3]

Reactions

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Iodide is oxidised to iodine

SOF6 + 2I + H2O → SO2F2 + I2 + 2HF + 2F

Alkalis such as potassium hydroxide react

2SOF6 + 12OH → O2 + 10F + 5H2O + 2SO3F

Alkenes react to add to a double bond, with -OSF5 on one carbon, and -F on the other.

C2H4 + SOF6 → FH2CCH2OSF5.[4]
C2F4 + SOF6 → CF3CF2OSF5.[4] C2SOF10 boils at 15°C
SOF6 + ClCH=CH2 → FClCH-CH2-O-SF5[5]
SOF6 + FCH=CH2 → F2CH-CH2-O-SF5[5]
SOF6 + F2C=CH2 → F3C-CH2-O-SF5[5]
SOF6 + SOF4 → mixture of SF6, SOF4, bis-(pentafluorosulfur) peroxide F5SOOSF5 and bis-(pentafluorosulfur) oxide F5SOSF5.[4]

Thermal decomposition produces sulfur hexafluoride and oxygen.

2SOF6 heat over 210° → 2SF6 + O2.[4]

Some reactions of SOF6 result in fluorination of other molecules

SOF6 + CO → F2CO + SOF4.[4]
SOF6 + F2CO → SF5OOCF3[6]
SOF6 + SO3 → F5SOOSO2F[6]
SOF6 + N2F4 → F5SONF2[6]
3SOF6 + Br22BrF3 + 3SOF4[6]
5SOF6 + I2 → 2IF5 + 5SOF4[6]
PF3 + SOF6PF5 + SOF4[6]
NO2 + SOF6 → 2NO2F[6]

References

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  1. ^ a b c d e Dudley, F. B.; Cady, G. H.; Eggers, D. F. (April 1956). "Pentafluorosulfur Hypofluorite and Thionyl Tetrafluoride". Journal of the American Chemical Society. 78 (8): 1553–1557. doi:10.1021/ja01589a013.
  2. ^ a b Crawford, Roger A.; Dudley, Frank B.; Hedberg, Kenneth (October 1959). "A Verification of the Molecular Structure of Pentafluorosulfur Hypofluorite (SF5OF) by Electron Diffraction". Journal of the American Chemical Society. 81 (20): 5287–5288. doi:10.1021/ja01529a009.
  3. ^ Emsley, J. W.; Feeney, J.; Sutcliffe, L. H. (22 October 2013). High Resolution Nuclear Magnetic Resonance Spectroscopy. Elsevier. p. 949. ISBN 9781483184081.
  4. ^ a b c d e Williamson, Stanley M.; Cady, George H. (August 1962). "Reactions of Pentafluorosulfur Hypofluorite". Inorganic Chemistry. 1 (3): 673–677. doi:10.1021/ic50003a044.
  5. ^ a b c Williamson, Stanley M. (1963). "On the Reaction of Pentafluorosulfur Hypofluorite with Unsymmetrical Two-Carbon Alkenes". Inorganic Chemistry. 2 (2): 421–422. doi:10.1021/ic50006a050.
  6. ^ a b c d e f g Tattershall, B.W.; Cady, George H. (December 1967). "Reactions of pentafluorosulphur hypofluorite (SF5OF) with Cl2, Br2, I2, NO2, and PF3". Journal of Inorganic and Nuclear Chemistry. 29 (12): 3003–3005. doi:10.1016/0022-1902(67)80134-9.