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Iodine heptafluoride

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Iodine Heptafloride
Structure of the iodine heptafluoride molecule
Iodine heptafluoride
Iodine heptafluoride
Iodine heptafluoride
Iodine heptafluoride
Names
Other names
iodine fluoride
heptafluoroiodine
Identifiers
ECHA InfoCard 100.037.241 Edit this at Wikidata
Properties
IF7
Molar mass 259.90 g/mol1
Density 2.6 g/cm3 (6 °C)
2.7 g/cm3 (25 °C)
Melting point 4.5°C (triple point)
Boiling point 4.8°C (sublimes at 1 atm)
soluble [1]
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Iodine heptafluoride, also known as iodine(VII) fluoride or even iodine fluoride, is the compound IF7.[2][3] It has an unusual pentagonal bipyramidal structure, as predicted by VSEPR theory.[4] The molecule can undergo a pseudorotational rearrangement like the Berry mechanism but for a hepta coordinated system.[5] 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 vapours 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.[6][7]

Safety considerations

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

References

  1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
  2. ^ Macintyre, J. E. (Ed.). (1992). Dictionary of Inorganic Compounds (Vol. 3). London: Chapman & Hall.
  3. ^ O'Neil, Maryadele J. (Ed.). (2001). The Merck Index (13th ed.). Whitehouse Station, NJ: Merck.
  4. ^ K. O. Christe, E. C. Curtis, D. A. Dixon (1993). "On the problem of heptacoordination: vibrational spectra, structure, and fluxionality of iodine heptafluoride". Industrial & Engineering Chemistry. 115 (4): 1520–1526. doi:10.1021/ja00057a044.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ W. J. Adams, H. Bradford Thompson, L. S. Bartell (1970). "Structure, Pseudorotation, and Vibrational Mode Coupling in IF7: An Electron Diffraction Study". Journal of Chemical Physics. 53 (10): 4040–4046. doi:10.1063/1.1673876.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ W. C. Schumb, M. A. Lynch, Jr. (1950). "Iodine Heptafluoride". Industrial & Engineering Chemistry. 42 (7): 1383–1386. doi:10.1021/ie50487a035.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Ruff O., Keim R. (1930). ""Das Jod-7-fluorid" (The iodine-7-fluoride)". Zeitschrift für Anorganische und Allgemeine Chemie. 193 (1/2): 176–186. doi:10.1002/zaac.19301930117.