Iodine heptafluoride

Chembox new
Name = Iodine Heptafloride
ImageFile = Iodine-heptafluoride-2D-dimensions.png ImageName = Structure of the iodine heptafluoride molecule
ImageFileL1 = Iodine-heptafluoride-3D-balls.png ImageNameL1 = Iodine heptafluoride
ImageFileR1 = Iodine-heptafluoride-3D-vdW.png ImageNameR1 = Iodine heptafluoride
OtherNames = iodine fluoride
heptafluoroiodine
Section1 = Chembox Identifiers
CASNo = 16921-96-3
Section2 = Chembox Properties
Formula = IF_{7
MolarMass = 259.89 g mol⁻¹
Density = 2.7 g cm⁻³ (solid)
Solvent = other solvents
SolubleOther = ? g L⁻¹
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 IF₇ [Macintyre, J. E. (Ed.). (1992). "Dictionary of Inorganic Compounds" (Vol. 3). London: Chapman & Hall.] [O'Neil, Maryadele J. (Ed.). (2001). "The Merck Index" (13th ed.). Whitehouse Station, NJ: Merck.] . It has an unusual pentagonal bipyramidal structure, as predicted by VSEPR theory. [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] The molecule can undergo a pseudorotational rearangment like the Berry mechanism but for a hepta coordinated system. [cite journal
title = Structure, Pseudorotation, and Vibrational Mode Coupling in IF₇: 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] 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

IF₇ is prepared by passing F₂ through liquid IF₅ at 90 °C, then heating the vapors to 270 °C. Alternately, this compound can be prepared from fluorine and dried PdI₂ or KI to minimize the formation of IOF₅, an impurity arising by hydrolysis. [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] [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]

afety considerations

IF₇ is highly irritating to both the skin and the mucous membranes.

References

External links

* [http://webbook.nist.gov/cgi/cbook.cgi?ID=C16921963 WebBook page for IF7]
* [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]