Antimony pentachloride is a chemical compound with the formula SbCl5. It is a colourless oil, but typical samples are yellowish due to dissolved chlorine. Owing to its tendency to hydrolyse to hydrochloric acid, SbCl5 is a highly corrosive substance and must be stored in glass or PTFE containers.

Preparation and structure

Antimony pentachloride is prepared by passing chlorine gas into molten antimony trichloride:

SbCl3 + Cl2 → SbCl5

Gaseous SbCl5 has a trigonal bipyramidal structure.[6]

Reactions

This compounds reacts with water to form antimony pentoxide and hydrochloric acid:[7]

2 SbCl5 + 5 H2O → Sb2O5 + 10 HCl

The mono- and tetrahydrates are known, SbCl5·H2O and SbCl5·4H2O.

This compound forms adducts with many Lewis bases. SbCl5 is a soft Lewis acid and its ECW model parameters are EA = 3.64 and CA = 10.42. It is used as the standard Lewis acid in the Gutmann scale of Lewis basicity.[8][9]

It is also a strong oxidizing agent.[10] For example aromatic ethers are oxidized to their radical cations according to the following stoichiometry:[11]

3 SbCl5 + 2 ArH → 2 (ArH+)(SbCl6−) + SbCl3

Applications

Antimony pentachloride is used as a polymerization catalyst and for the chlorination of organic compounds.

Precautions

Antimony pentachloride is a highly corrosive substance that should be stored away from heat and moisture. It is a chlorinating agent and, in the presence of moisture, it releases hydrogen chloride gas. Because of this, it may etch even stainless-steel tools (such as needles), if handled in a moist atmosphere. It should not be handled with non-fluorinated plastics (such as plastic syringes, plastic septa, or needles with plastic fittings), since it melts and carbonizes plastic materials.[12]

References

  1. ^ a b c "Antimony pentachloride (UK PID)".
  2. ^ a b c Sigma-Aldrich Co., Antimony(V) chloride. Retrieved on 2014-05-29.
  3. ^ a b c "Antimony(V) chloride".
  4. ^ Antimony pentachloride in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-05-29)
  5. ^ a b NIOSH Pocket Guide to Chemical Hazards. "#0036". National Institute for Occupational Safety and Health (NIOSH).
  6. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  7. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  8. ^ V. Gutmann (1976). "Solvent effects on the reactivities of organometallic compounds". Coord. Chem. Rev. 18 (2): 225–255. doi:10.1016/S0010-8545(00)82045-7.
  9. ^ Cramer, R. E.; Bopp, T. T. (1977). "Graphical display of the enthalpies of adduct formation for Lewis acids and bases". Journal of Chemical Education. 54: 612–613. doi:10.1021/ed054p612. The plots shown in this paper used older parameters. Improved E&C parameters are listed in ECW model.
  10. ^ Connelly, N. G.; Geiger, W. E. (1996). "Chemical Redox Agents for Organometallic Chemistry". Chem. Rev. 96 (2): 877–922. doi:10.1021/cr940053x. PMID 11848774.
  11. ^ Rathore, R.; Kumar, A. S.; Lindeman, S. V.; Kochi, J. K. (1998). "Preparation and Structures of Crystalline Aromatic Cation-Radical Salts. Triethyloxonium Hexachloroantimonate as a Novel (One-Electron) Oxidant". The Journal of Organic Chemistry. 63 (17): 5847–5856. doi:10.1021/jo980407a. PMID 11672186.
  12. ^ Shekarchi, M.; Behbahani, F. K Catal. Lett. 2017 147 2950. doi:10.1007/s10562-017-2194-2

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