Thionyl fluoride

Thionyl fluoride
Identifiers
CAS number 7783-42-8 N
PubChem 24548
ChemSpider 22954 Y
Jmol-3D images Image 1
Properties
Molecular formula SOF2
Appearance colorless gas
Melting point

-110.5°C

Boiling point

-43.8°C

Hazards
R-phrases R36/37/38[1]
Related compounds
Related oxohalides Thionyl chloride
Thionyl bromide
Related compounds Nitrosyl fluoride
Carbonyl fluoride
 N (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Thionyl fluoride is the inorganic compound with the formula SOF2. This colourless gas is mainly of theoretical interest, but it is a product of the degradation of sulfur hexafluoride, an insulator in electrical equipment. The molecule adopts a pyramidal structure, with C2v symmetry. The S-O and S-F distances are 1.42 and 1.58 A, respectively. The O-S-F and F-S-F angles are 106.2 and 92.2°, respectively. Thionyl chloride and thionyl bromide have similar structures, although these compounds are liquid at room temperature. Mixed halides are also known, such as SOClF.[2]

Synthesis and reactions

Thionyl fluoride can be produced by the reaction of thionyl chloride with fluoride sources such as antimony trifluoride.[3][4]

3 SOCl2 + 2SbF3 → 3SOF2 + 2SbCl3

Alternatively, it arises via the fluorination of sulfur dioxide:[4]

SO2 + 2PF5 → SOF2 + POF3

Thionyl fluoride arises as a fleeting intermediate from the decomposition of sulfur hexafluoride as the result of electrical discharges which generate sulfur tetrafluoride. SF4 hydrolyzes to give thionyl fluoride, which in turn hydrolyzes further as described below.[5]

As expected from the behavior of the other thionyl halides, this compound hydrolyzes readily, giving hydrogen fluoride and sulfur dioxide:[4]

SOF2 + H2O → 2HF + SO2

In contrast to thionyl chloride and bromide, thionyl fluoride is not useful in organofluorine chemistry. The related derivative, sulfur tetrafluoride is however a useful reagent.

References

  1. ^ "Safety (MSDS) data for thionyl fluoride". Oxford University. 2005-09-02. http://msds.chem.ox.ac.uk/TH/thionyl_fluoride.html. Retrieved 2008-07-29. 
  2. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
  3. ^ W. C. Smith, E. L. Muetterties “Thionyl Fluoride” Inorganic Syntheses 1960, Volume 6, pages: 162-163. doi:10.1002/9780470132371.ch50
  4. ^ a b c Holleman, Arnold F. (2001). Inorganic Chemistry. Academic Press. pp. 542. ISBN 0-12-352651-5. http://books.google.com/?id=LxhQPdMRfVIC&pg=PA542&dq=%22Thionyl+fluoride%22. Retrieved 2008-07-29 
  5. ^ Pepi, Federico; Andreina Ricci, Marco Di Stefano, Marzio Rosi, Giuseppe D'Arcangelo (September 18 2002). "Thionyl Fluoride from Sulfur Hexafluoride Corona Discharge Decomposition: Gas-Phase Chemistry of (SOF2)H+ Ions". Journal of Physical Chemistry A (American Chemical Society) 106 (40): 9261–9266. doi:10.1021/jp021074v. http://pubs.acs.org/cgi-bin/abstract.cgi/jpcafh/2002/106/i40/abs/jp021074v.html.