Antimony pentafluoride 3276019 223828636 2008-07-06T00:52:08Z Mild Bill Hiccup 5202324 /* External links */ spelling {{Chembox new | ImageFileL1 = Antimony-pentafluoride-2D.png | ImageSizeL1 = 120px | ImageNameL1 = Antimony pentafluoride | ImageFileR1 = Antimony-pentafluoride-monomer-3D-balls.png | ImageSizeR1 = 120px | ImageNameR1 = Antimony pentafluoride | IUPACName = antimony(V) fluoride | OtherNames = antimony pentafluoride<br>pentafluoroantimony | Section1 = {{Chembox Identifiers | CASNo = 7783-70-2 | PubChem = | SMILES = }} | Section2 = {{Chembox Properties | Formula = SbF<sub>5</sub> | MolarMass = 216.74 g mol<sup>−1</sup> | Appearance = | Density = 4.07 g cm<sup>-3</sup> | MeltingPt = 8.3 °C (281.3 K) | BoilingPt = 141 °C (414 K) | Solubility = Reacts with water}} | SolubleOther = | Solvent = [[Sulfur dioxide|SO<sub>2</sub>]], [[Sulfuryl chloride fluoride|SO<sub>2</sub>FCl]] | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | Autoignition = }} | Section7 = {{Chembox Hazards | ExternalMSDS = | EUClass = | EUIndex = | MainHazards = | NFPA-H = 4 | NFPA-F = 0 | NFPA-R = 1 | NFPA-O = | RPhrases = | SPhrases = | RSPhrases = | FlashPt = | Autoignition = | ExploLimits = | PEL = }} }} '''Antimony pentafluoride''' is the [[chemical compound]] with the formula [[Antimony|Sb]][[Fluorine|F]]<sub>5</sub>. This colourless, viscous liquid is a valuable [[Lewis acid]] and a component of the [[superacid]] [[fluoroantimonic acid]], the strongest known acid. Some features that give the compound scientific interest are its [[Lewis acid]]ity and that it also reacts with almost all known compounds.<ref>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.</ref> ==Structure and chemical reactions== In the gas phase, SbF<sub>5</sub> adopts a trigonal bipyramidal structure of D<sub>3h</sub> [[symmetry group|point group symmetry]] (see picture). The structure is more complex in the liquid and solid state. The liquid contains polymers wherein each Sb is octahedral, the structure being described with the formula [SbF<sub>4</sub>(&mu;-F)<sub>2</sub>]<sub>n</sub>. The crystalline material is tetrameric, i.e. it has the formula [SbF<sub>4</sub>(&mu;-F)]<sub>4</sub>. The Sb-F bonds are 2.02 Å within the eight-membered Sb<sub>4</sub>F<sub>4</sub> ring; the remaining fluoride ligands radiating from the four Sb centers are shorter at 1.82 Å.<ref>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}}</ref> The related species PF<sub>5</sub> and AsF<sub>5</sub> are [[monomer]]ic in the solid and liquid states, probably due to the smaller sizes of the central atom, which limits their coordination number. BiF<sub>5</sub> is a polymer.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> SbF<sub>5</sub> is a strong Lewis acid, exceptionally so toward sources of F<sup>−</sup> to give the very stable anion [SbF<sub>6</sub>]<sup>−</sup>. The latter reacts with additional SbF<sub>5</sub> to give [Sb<sub>2</sub>F<sub>11</sub>]<sup>−</sup>. In the same way that SbF<sub>5</sub> enhances the [[Brønsted-Lowry acid|Brønsted acidity]] of HF, it enhances the [[oxidation|oxidizing]] power of F<sub>2</sub>. This effect is illustrated by the oxidation of [[oxygen]]:<ref>Shamir, J.; Binenboym, J. "Dioxygenyl Salts" Inorganic Syntheses, 1973, XIV, 109-122. {{ISSN|0073-8077}}</ref> :SbF<sub>5</sub> + ½F<sub>2</sub> + O<sub>2</sub> → [O<sub>2</sub>]<sup>+</sup>[SbF<sub>6</sub>]<sup>-</sup> Antimony pentafluoride has also been used in the first discovered chemical reaction that produces [[fluorine]] gas from fluoride compounds: :2 SbF<sub>5</sub> + [[Potassium|K]]<sub>2</sub>[[Manganese|Mn]]F<sub>6</sub> → 2 KSbF<sub>6</sub> + MnF<sub>3</sub> + 0.5 F<sub>2</sub> The driving force for this reactions is the high affinity of SbF<sub>5</sub> for F<sup>-</sup>, which is the same property which recommends the use of SbF<sub>5</sub> to generate superacids. ==Safety== SbF<sub>5</sub> reacts violently with many compounds, often releasing dangerous [[hydrogen fluoride]]. ==References== {{reflist}} <div class="references-small"> *IPCS, CEC 2005. [http://www.inchem.org/documents/icsc/icsc/eics0220.htm "ANTIMONY PENTAFLUORIDE (ICSC)] Retrieved [[May 13]], [[2006]]. *Barbalace, Kenneth. [http://environmentalchemistry.com/yogi/chemicals/cn/Antimony%A0Pentafluoride.html "Chemical Database - Antimony Pentafluoride"]. 1995 - 2006. Retrieved May 13, 2006. </div> ==External links== *[http://www.npi.gov.au/database/substance-info/profiles/10.html National Pollutant Inventory - Antimony and compounds fact sheet] *[http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory - Fluoride compounds fact sheet] [[Category:Superacids]] [[Category:Antimony compounds]] [[Category:Fluorides]] {{inorganic-compound-stub}} [[ar:فلوريد أنتيموان خماسي]] [[cs:Fluorid antimoničný]] [[de:Antimon(V)-fluorid]] [[ja:五フッ化アンチモン]] [[pl:Pentafluorek antymonu]] [[pt:Pentafluoreto de antimônio]] [[fi:Antimonipentafluoridi]] [[zh:五氟化锑]]