Iodine heptafluoride 2332266 216895509 2008-06-03T18:33:34Z 131.111.237.216 changed melting point from 6.5 to 4.5 (as in text) {{Chembox new | Name = Iodine heptafluoride | ImageFile = Iodine-heptafluoride-2D-dimensions.png <!-- | ImageSize = 120px --> | ImageName = Structure of the iodine heptafluoride molecule | ImageFileL1 = Iodine-heptafluoride-3D-balls.png <!-- | ImageSizeL1 = 120px --> | ImageNameL1 = Iodine heptafluoride | ImageFileR1 = Iodine-heptafluoride-3D-vdW.png <!-- | ImageSizeR1 = 120px --> | ImageNameR1 = Iodine heptafluoride | OtherNames = iodine fluoride<br />heptafluoroiodine | Section1 = {{Chembox Identifiers | CASNo = 16921-96-3 }} | Section2 = {{Chembox Properties | Formula = IF<sub>7 | MolarMass = 259.89 g mol<sup>−1</sup> | Density = 2.7 g cm<sup>−3</sup> (solid) | Solvent = other solvents | SolubleOther = ? g L<sup>−1</sup> | MeltingPt = 4.5°C (triple point) | BoilingPt = 4.8°C (sublimes at 1 atm)}} }} '''Iodine heptafluoride''', also known as iodine(VII) fluoride or even iodine fluoride, is the compound [[iodine|I]][[fluoride|F]]<sub>7</sub><ref>Macintyre, J. E. (Ed.). (1992). ''Dictionary of Inorganic Compounds'' (Vol. 3). London: Chapman & Hall.</ref><ref>O'Neil, Maryadele J. (Ed.). (2001). ''The Merck Index'' (13th ed.). Whitehouse Station, NJ: Merck.</ref>. It has an unusual [[Pentagonal bipyramid molecular geometry|pentagonal bipyramidal]] structure, as predicted by [[VSEPR theory]].<ref>{{cite journal | title = On the problem of heptacoordination: vibrational spectra, structure, and fluxionality of iodine heptafluoride | author = K. O. Christe, E. C. Curtis, D. A. Dixon | journal = [[Industrial & Engineering Chemistry]] | year = 1993 | volume = 115 | issue = 4 | pages = 1520–1526 | doi = 10.1021/ja00057a044 }}</ref> The molecule can undergo a [[pseudorotation]]al rearangment like the [[Berry mechanism]] but for a hepta coordinated system.<ref>{{cite journal | title = Structure, Pseudorotation, and Vibrational Mode Coupling in IF<sub>7</sub>: An Electron Diffraction Study | author = W. J. Adams, H. Bradford Thompson, L. S. Bartell | journal = [[Journal of Chemical Physics]] | year = 1970 | volume = 53 | issue = 10 | pages = 4040–4046 | doi = 10.1063/1.1673876 }}</ref> It forms colourless crystals, which melt at 4.5°C: the liquid range is extremely narrow, with the boiling point at 4.77°C. The dense vapor has a mouldy, acrid odour. ==Preparation== IF<sub>7</sub> is prepared by passing [[Fluorine|F<sub>2</sub>]] through liquid [[Iodine pentafluoride|IF<sub>5</sub>]] at 90 °C, then heating the vapors to 270 °C. Alternately, this compound can be prepared from fluorine and dried PdI<sub>2</sub> or KI to minimize the formation of IOF<sub>5</sub>, an impurity arising by hydrolysis.<ref>{{cite journal | title = Iodine Heptafluoride | author = W. C. Schumb, M. A. Lynch, Jr. | journal = [[Industrial & Engineering Chemistry]] | year = 1950 | volume = 42 | issue = 7 | pages = 1383–1386 | doi = 10.1021/ie50487a035 }}</ref> <ref>{{cite journal | title = "Das Jod-7-fluorid" (The iodine-7-fluoride) | author = Ruff O., Keim R. | journal = Zeitschrift für Anorganische un Allgemeine Chemie | year = 1930 | volume = 193 | issue = 1/2 | pages = 176–186 | doi = 10.1002/zaac.19301930117 }}</ref> ==Safety considerations== IF<sub>7</sub> is highly irritating to both the skin and the mucous membranes. ==References== <references/> ==External links== *[http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory - Flouride and compounds fact sheet] *[http://www.webelements.com/webelements/compounds/text/I/F7I1-16921963.html web elements listing] [[Category:Fluorides]] [[Category:Iodine compounds]] [[Category:Interhalogen compounds]] {{inorganic-compound-stub}} [[pt:Heptafluoreto de iodo]]