Iodine heptafluoride

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Iodine heptafluoride
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Iodine heptafluoride Iodine-heptafluoride-3D-balls.png
Iodine heptafluoride
Iodine heptafluoride Iodine-heptafluoride-3D-vdW.png
Iodine heptafluoride
Names
Other names
Iodine(VII) fluoride
Heptafluoroiodine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.037.241 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/F7I/c1-8(2,3,4,5,6)7 Yes check.svgY
    Key: XRURPHMPXJDCOO-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/F7I/c1-8(2,3,4,5,6)7
    Key: XRURPHMPXJDCOO-UHFFFAOYAO
  • FI(F)(F)(F)(F)(F)F
Properties
IF7
Molar mass 259.90 g/mol
Appearancecolorless gas
Density 2.6 g/cm3 (6 °C)
2.7 g/cm3 (25 °C)
Melting point 4.5 °C (40.1 °F; 277.6 K) (triple point)
Boiling point 4.8 °C (40.6 °F; 277.9 K) (sublimes at 1 atm)
soluble [1]
Related compounds
Related compounds
 iodine pentafluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Iodine heptafluoride is an interhalogen compound with the chemical formula I F 7. [2] [3] It has an unusual pentagonal bipyramidal structure, with D5h symmetry, as predicted by VSEPR theory. [4] The molecule can undergo a pseudorotational rearrangement called the Bartell mechanism, which is like the Berry mechanism but for a heptacoordinated system. [5]

Contents

Below 4.5 °C, IF7 forms a snow-white powder of colorless crystals, melting at 5-6 °C. However, this melting is difficult to observe, as the liquid form is thermodynamically unstable at 760 mmHg: instead, the compound begins to sublime at 4.77 °C. The dense vapor has a mouldy, acrid odour. [6] [7]

Preparation

IF7 is prepared by passing F2 through liquid IF5 at 90 °C, then heating the vapours to 270 °C. Alternatively, this compound can be prepared from fluorine and dried palladium or potassium iodide to minimize the formation of IOF5, an impurity arising by hydrolysis. [8] [9] Iodine heptafluoride is also produced as a by-product when dioxygenyl hexafluoroplatinate is used to prepare other platinum(V) compounds such as potassium hexafluoroplatinate(V), using potassium fluoride in iodine pentafluoride solution: [10]

2 O2PtF6 + 2 KF + IF5 → 2 KPtF6 + 2 O2 + IF7

Reactions

Iodine heptafluoride decomposes at 200 °C to fluorine gas and iodine pentafluoride. [11]

Safety considerations

IF7 is highly irritating to both the skin and the mucous membranes. It also is a strong oxidizer and can cause fire on contact with organic material.

Related Research Articles

In chemistry, an interhalogen compound is a molecule which contains two or more different halogen atoms and no atoms of elements from any other group.

Iodine pentafluoride is an interhalogen compound with chemical formula IF5. It is one of the fluorides of iodine. It is a colorless liquid, although impure samples appear yellow. It is used as a fluorination reagent and even a solvent in specialized syntheses.

Antimony pentafluoride is the inorganic compound with the formula SbF5. This colourless, viscous liquid is a strong Lewis acid and a component of the superacid fluoroantimonic acid, formed upon mixing liquid HF with liquid SbF5 in 1:1 ratio. It is notable for its strong Lewis acidity and the ability to react with almost all known compounds.

<span class="mw-page-title-main">Hydrogen fluoride</span> Chemical compound

Hydrogen fluoride (fluorane) is an inorganic compound with chemical formula HF. It is a very poisonous, colorless gas or liquid that dissolves in water to yield an aqueous solution termed hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers, e.g. polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils at near room temperature, much higher than other hydrogen halides.

<span class="mw-page-title-main">Technetium hexafluoride</span> Chemical compound

Technetium hexafluoride or technetium(VI) fluoride (TcF6) is a yellow inorganic compound with a low melting point. It was first identified in 1961. In this compound, technetium has an oxidation state of +6, the highest oxidation state found in the technetium halides. In this respect, technetium differs from rhenium, which forms a heptafluoride, ReF7. Technetium hexafluoride occurs as an impurity in uranium hexafluoride, as technetium is a fission product of uranium (spontaneous fission in natural uranium, possible contamination from induced fission inside the reactor in reprocessed uranium). The fact that the boiling point of the hexafluorides of uranium and technetium are very close to each other presents a problem in using fluoride volatility in nuclear reprocessing.

<span class="mw-page-title-main">Dioxygenyl</span> Chemical compound

The dioxygenyl ion, O+
2, is a rarely-encountered oxycation in which both oxygen atoms have a formal oxidation state of +1/2. It is formally derived from oxygen by the removal of an electron:

Dioxygenyl hexafluoroplatinate is a compound with formula O2PtF6. It is a hexafluoroplatinate of the unusual dioxygenyl cation, O2+, and is the first known compound containing this cation. It can be produced by the reaction of dioxygen with platinum hexafluoride. The fact that PtF
6 is strong enough to oxidise O
2, whose first ionization potential is 12.2 eV, led Neil Bartlett to correctly surmise that it might be able to oxidise xenon (first ionization potential 12.13 eV). This led to the discovery of xenon hexafluoroplatinate, which proved that the noble gases, previously thought to be inert, are able to form chemical compounds.

<span class="mw-page-title-main">Rhenium heptafluoride</span> Chemical compound

Rhenium heptafluoride is the compound with the formula ReF7. It is a yellow low melting solid and is the only thermally stable metal heptafluoride. It has a distorted pentagonal bipyramidal structure similar to IF7, which was confirmed by neutron diffraction at 1.5 K. The structure is non-rigid, as evidenced by electron diffraction studies.

Arsenic trifluoride is a chemical compound of arsenic and fluorine with the chemical formula AsF3. It is a colorless liquid which reacts readily with water.

Iodine fluoride may refer to:

Iodine monofluoride is an interhalogen compound of iodine and fluorine with formula IF. It is a chocolate-brown solid that decomposes at 0 °C, disproportionating to elemental iodine and iodine pentafluoride:

<span class="mw-page-title-main">Potassium hexafluoronickelate(IV)</span> Chemical compound

Potassium hexafluoronickelate(IV) is an inorganic compound with the chemical formula K
2NiF
6. It can be produced through the reaction of potassium fluoride, nickel dichloride, and fluorine.

<span class="mw-page-title-main">Rhenium hexafluoride</span> Chemical compound

Rhenium hexafluoride, also rhenium(VI) fluoride, (ReF6) is a compound of rhenium and fluorine and one of the seventeen known binary hexafluorides.

Chromium pentafluoride is the inorganic compound with the chemical formula CrF5. It is a red volatile solid that melts at 34 °C. It is the highest known chromium fluoride, since the hypothetical chromium hexafluoride has not yet been synthesized.

Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.

Neptunium(V) fluoride or neptunium pentafluoride is a chemical compound of neptunium and fluorine with the formula NpF5.

<span class="mw-page-title-main">Hexafluoroarsenate</span> Chemical compound

The hexafluoroarsenate anion is a chemical species with formula AsF−6. Hexafluoroarsenate is relatively inert, being the conjugate base of the notional superacid hexafluoroarsenic acid.

<span class="mw-page-title-main">Iodosyl trifluoride</span> Chemical compound

Iodosyl trifluoride is an inorganic compound of iodine, fluorine, and oxygen with the chemical formula IOF3.

Iodosyl pentafluoride is an inorganic compound of iodine, fluorine, and oxygen with the chemical formula IOF5.

<span class="mw-page-title-main">Iodyl fluoride</span> Chemical compound

Iodyl fluoride is an inorganic compound of iodine, fluorine, and oxygen with the chemical formula IO2F. The compound was initially synthesized in 1951.

References

  1. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN   0-07-049439-8
  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". Journal of the American Chemical Society . 115 (4): 1520–1526. doi:10.1021/ja00057a044.
  5. ↑ W. J. Adams; H. Bradford Thompson; L. S. Bartell (1970). "Structure, Pseudorotation, and Vibrational Mode Coupling in IF7: An Electron Diffraction Study" (PDF). Journal of Chemical Physics . 53 (10): 4040–4046. Bibcode:1970JChPh..53.4040A. doi:10.1063/1.1673876. hdl: 2027.42/71219 .
  6. ↑ Lide, David R. (2011). The CRC Handbook of Chemistry and Physics , 89th ed. p.  4-67.
  7. ↑ Ruff & Keim 1930 , pp. 180–182: "Das reine Jod-7-fluorid ist bei Zimmer­temperatur ein farbloses Gas, das an der Luft infolge seiner Umsetzung mit dem Wasser­dampf Nebel bildet und muffig sauer riecht. Beim Abkühlen wird es je nach den Versuchs­bedingungen als leicht bewegliche, farblose Flüssigkeit als schneeweißes lockeres Pulver oder in Form farbloser Kristalle erhalten....Die Schmelz­temperatur wurde durch Eintauchen von Proben, die in Quarzröhrchen eingeschmolzen waren, in Bäder passender Temperatur ermittelt und zu 5 bis 6° C gefunden. [Durch] Messung der Dampfdrucke...gelangt man zu der Gleichung
    ....Für den Druck von 760 mm errechnet sich eine Temperatur von 4,5° C. [Pure iodine heptafluoride is at room temperature a colorless gas, which forms a fog in air on account of its reaction with the humidity and smells musty and acrid. When cooled, it takes the form, depending on experimental conditions, of a free-flowing colorless liquid, a loose snow-white powder, or colorless crystals....The melting point was measured by immersion of a probe in a bath of the right temperature, which was melting in a little quartz tube and found to be 5‑6 °C. [From] measurement of the vapor pressure...one arrives at the equation
    ....At a pressure of 760 mm it computes a temperature of 4.5 °C.]"
  8. ↑ Schumb, W. C.; Lynch, M. A. (1950). "Iodine Heptafluoride". Industrial & Engineering Chemistry . 42 (7): 1383–1386. doi:10.1021/ie50487a035.
  9. ↑ Ruff & Keim 1930.
  10. ↑ Beveridge, A. D.; Clark, H. C. (1967). "Pentahalides of the Transition Metals". In Gutmann, Viktor (ed.). Halogen Chemistry. Vol. 3. Academic Press. pp. 179–226. ISBN   9780323148474.
  11. ↑ Кнунянц, И. Л. (1990). Химическая энциклопедия : в пяти томах (in Russian). Советская Энциклопедия. p. 496. ISBN   5-85270-008-8. OCLC   19556260.

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