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Antimony pentafluoride
Antimony pentafluoride	Antimony pentafluoride
Names
	IUPAC name Antimony pentafluoride
	Systematic IUPAC name Pentafluoro-λ5-stibane
	Other names Antimony(V) fluoride; pentafluoridoantimony
Identifiers
CAS Number	7783-70-2 ;
3D model (JSmol)	Interactive image;
ChemSpider	22963 ;
ECHA InfoCard	100.029.110
EC Number	232-021-8;
PubChem CID	24557;
RTECS number	CC5800000;
UNII	6C93R71VRF ;
UN number	1732
CompTox Dashboard (EPA)	DTXSID00893075;
	InChI InChI=1S/5FH.Sb/h51H;/q;;;;;+5/p-5 Key: VBVBHWZYQGJZLR-UHFFFAOYSA-I ; InChI=1/5FH.Sb/h51H;/q;;;;;+5/p-5/rF5Sb/c1-6(2,3,4)5 Key: VBVBHWZYQGJZLR-NMXCDXEPAW;
	SMILES F[Sb](F)(F)(F)F;
Properties
Chemical formula	SbF5
Molar mass	216.74 g/mol
Appearance	colorless oily, viscous liquid ; hygroscopic
Odor	pungent, sharp
Density	2.99 g/cm3
Melting point	8.3 °C (46.9 °F; 281.4 K)
Boiling point	149.5 °C (301.1 °F; 422.6 K)
Solubility in water	Reacts
Solubility	soluble in KF, liquid SO2
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Extremely toxic, corrosive, hazardous to health. Releases hydrofluoric acid upon contact with water and biological tissues. Strong oxidizing agent.
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300+H310+H330, H314, H411, H412
Precautionary statements	P260, P261, P264, P270, P271, P273, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P330, P363, P391, P405, P501
NFPA 704 (fire diamond)	4 0 3 W; OX
Flash point	noncombustible
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	270 mg/kg (mouse, subcutaneous)
LC50 (median concentration)	270 mg/m3 (mouse, inhalation)
LCLo (lowest published)	15 mg/m3 (rat, inhalation, 2 hours)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.5 mg/m3 (as Sb)
REL (Recommended)	TWA 0.5 mg/m3 (as Sb)
IDLH (Immediate danger)	50 mg/m3
Safety data sheet (SDS)	ICSC 0220
Related compounds
Other anions	Antimony pentachloride
Other cations	Phosphorus pentafluoride; Arsenic pentafluoride; Bismuth pentafluoride
Related compounds	Antimony trifluoride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Antimony pentafluoride is the inorganic compound with the formula Sb F₅. This colourless, viscous liquid is a strong Lewis acid and a component of the superacid fluoroantimonic acid, formed upon mixing liquid HF with liquid SbF₅ in 1:1 ratio. It is notable for its strong Lewis acidity and the ability to react with almost all known compounds.^[4]

Preparation

Antimony pentafluoride is prepared by the reaction of antimony pentachloride with anhydrous hydrogen fluoride:^[5]

SbCl₅ + 5 HF → SbF₅ + 5 HCl

It can also be prepared from antimony trifluoride and fluorine.^[6]

Structure and chemical reactions

In the gas phase, SbF₅ adopts a trigonal bipyramidal structure of D_3h point group symmetry (see picture). The material adopts a more complicated structure in the liquid and solid states. The liquid contains polymers wherein each Sb is octahedral, the structure being described with the formula [SbF₄(μ-F)₂]_n ((μ-F) denotes the fact that fluoride centres bridge two Sb centres). The crystalline material is a tetramer, meaning that it has the formula [SbF₄(μ-F)]₄. The Sb-F bonds are 2.02 Å within the eight-membered Sb₄F₄ ring; the remaining fluoride ligands radiating from the four Sb centers are shorter at 1.82 Å.^[7] The related species PF₅ and AsF₅ are monomeric in the solid and liquid states, probably due to the smaller sizes of the central atom, which limits their coordination number. BiF₅ is a polymer.^[8]

SbF₅ oxidizes oxygen in the presence of fluorine:^[9]

2 SbF₅ + F₂ + 2 O₂ → 2 [O₂]⁺[SbF₆]⁻

Antimony pentafluoride by itself is also a very strong oxidizing agent. Phosphorus burns on contact with it.

SbF₅ has also been used in the first discovered chemical reaction that produces fluorine gas from fluoride compounds:

4 SbF₅ + 2 K₂MnF₆ → 4 KSbF₆ + 2 MnF₃ + F₂

The driving force for this reaction is the high affinity of SbF₅ for F⁻, which is the same property that recommends the use of SbF₅ to generate superacids.

Hexafluoroantimonate

SbF₅ is a strong Lewis acid, exceptionally so toward sources of F⁻ to give the very stable anion [SbF₆]⁻, called hexafluoroantimonate. It is the conjugate base of the superacid fluoroantimonic acid. [SbF₆]⁻ is a weakly coordinating anion akin to PF₆⁻. Although it is only weakly basic, [SbF₆]⁻ does react with additional SbF₅ to give a centrosymmetric adduct:

SbF₅ + [SbF₆]⁻ → [Sb₂F₁₁]⁻

The [Sb₂F₁₁]⁻ anion is one of the ions found in HF/SbF₅ Mixture.

Safety

SbF₅ reacts violently with water. It reacts with many compounds, often releasing dangerous hydrogen fluoride. It is highly toxic and corrosive to the skin and eyes. It is a strong oxidizer.^[10]^[11]

References

^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.
^ ^a ^b NIOSH Pocket Guide to Chemical Hazards. "#0036". National Institute for Occupational Safety and Health (NIOSH).
^ World of Chemicals SDS
^ 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:10.1002/047084289X.
^ Sabina C. Grund, Kunibert Hanusch, Hans J. Breunig, Hans Uwe Wolf "Antimony and Antimony Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim doi:10.1002/14356007.a03_055.pub2
^ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 200.
^ Edwards, A. J.; Taylor, P. "Crystal structure of Antimony Pentafluoride" Journal of the Chemical Society, Chemical Communications 1971, pp. 1376-7.doi:10.1039/C29710001376
^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
^ Shamir, J.; Binenboym, J. "Dioxygenyl Salts" Inorganic Syntheses 1973, XIV, 109-122. ISSN 0073-8077
^ International Programme on Chemical Safety (2005). "Antimony pentafluoride". Commission of the European Communities (CEC). Retrieved 2010-05-10.
^ Barbalace, Kenneth (2006). "Chemical Database - Antimony Pentafluoride". Environmental Chemistry. Retrieved 2010-05-10.