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]]