Antimony pentafluoride

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Antimony pentafluoride

Systematic name	antimony(V) fluoride
Other names	antimony pentafluoride pentafluoroantimony
Molecular formula	SbF₅
Molar mass	216.74 g mol⁻¹
CAS number	[7783-70-2]
Solubility (water)	Reacts with water
Solubility in other solvents	SO₂,SO₂FCl
Melting point	8.3 °C (281.3 K)
Boiling point	141 °C (414 K)
NFPA 704	0 4 1
Disclaimer and references

Antimony pentafluoride is the chemical compound with the formula SbF₅. This colourless, viscous liquid is a valuable Lewis acid and a component of fluoroantimonic acid, the strongest known acid, i.e. a superacid. The very feature that make SbF₅ interesting also - its extraordinary Lewis acidity - also is responsible for the fact that it reacts with almost all known compounds,^[1]

1 Structure and chemical reactions
2 Safety
3 References
4 External links

[edit] Structure and chemical reactions

SbF₅ adopts a trigonal bipyramidal structure of D_3h point group symmetry. It is a strong Lewis acid, especially toward sources of F⁻ whereup it gives the relatively inert anion [SbF₆]⁻. The latter reacts with additional SbF₅ to give [Sb₂F₁₁]⁻.

In the same way that SbF₅ enhances the Brønsted acidity of HF, it enhances the oxidizing power of F₂. This effect is illustrated by the oxidation of oxygen:^[2]

SbF₅ + ½F₂ + O₂ → [O₂](SbF₆)

[edit] Safety

SbF₅ reacts violently with many compounds, often releasing dangerous hydrogen fluoride.

[edit] References

^ Olah, G. A.; Prakash, G. K. S.; Wang, Q.; Li, X.-y."Antimony(V) Fluoride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
^ Shamir, J.; Binenboym, J. "Dioxygenyl Salts" Inorganic Syntheses, 1973, XIV, 109-122. ISBN 07-071320-0.