Iodine oxide

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Iodine pentoxide (I2O5) Iodine-pentoxide-3D-balls.png
Iodine pentoxide (I2O5)

Iodine oxides are chemical compounds of oxygen and iodine. Iodine has only two stable oxides which are isolatable in bulk, iodine tetroxide and iodine pentoxide, but a number of other oxides are formed in trace quantities or have been hypothesized to exist. The chemistry of these compounds is complicated with only a few having been well characterized. Many have been detected in the atmosphere and are believed to be particularly important in the marine boundary layer. [1]

Contents

Iodine oxides [2]
Molecular formula I2OIO [3] IO2I2O4I2O5I2O6I4O9
Name diiodine oxide iodine monoxide iodine dioxide iodine tetroxide

(diiodine tetroxide)

Iodine pentoxide

(diiodine pentoxide)

Diiodine hexaoxide tetraiodine nonoxide
Structure I2OIOIO2O2IOIOO(IO2)2[IO2]+[IO4]I(OIO2)3
Molecular model Diiodine-oxide-3D-vdW.png Iodine-monoxide-3D-vdW.png Iodine-dioxide-3D-vdW.png Iodine-pentoxide-3D-vdW.png
CAS registry 39319-71-614696-98-113494-92-31024652-24-112029-98-065355-99-966523-94-2
Appearance Unknownpurple gasyellow solidyellow solidwhite crystalline solidyellow soliddark yellow solid
Oxidation state +1+2+4+3 and +5+5+5 and +7+3 and +5
Melting point not isolablenot isolablenot isolabledecomp. 100 °Cdecomp. 300350 °Cdecomp 150 °Cdecomp. 75 °C
Specific gravity 4.24.84.53
Solubility in water decomp. to HIO3 + I2187 g/100 mLdecomp. to HIO3 + I2

Diiodine monoxide has largely been the subject of theoretical study, [4] but there is some evidence that it may be prepared in a similar manner to dichlorine monoxide, via a reaction between HgO and I2. [5] The compound appears to be highly unstable but can react with alkenes to give halogenated products. [6]

Radical iodine oxide (IO), iodine dioxide (IO2) and iodine tetroxide ((I2O4) all possess significant and interconnected atmospheric chemistry. They are formed, in very small quantities, at the marine boundary layer by the photooxidation of diiodomethane, which is produced by macroalga such as seaweed or through the oxidation of molecular iodine, produced by the reaction of gaseous ozone and iodide present at the seasurface. [7] [8] Despite the small quantities produced (typically below ppt) they are thought to be powerful ozone depletion agents. [9] [10]

Diiodine pentoxide (I2O5) is the anhydride of iodic acid and the only stable anhydride of an iodine oxoacid.

Tetraiodine nonoxide (I4O9) has been prepared by the gas-phase reaction of I2 with O3 but has not been extensively studied. [11]

Iodate anions

Iodine oxides also form negatively charged anions, which (associated with complementary cations) are components of acids or salts. These include the iodates and periodates.

Their conjugate acids are:

Iodine oxidation state−1+1+3+5+7
Name Hydrogen iodide* Hypoiodous acid Iodous acid Iodic acid Periodic acid
FormulaHIHIOHIO2HIO3HIO4 or H5IO6

 The -1 oxidation state, hydrogen iodide, is not an oxide, but it is included in this table for completeness.

The periodates include two variants: metaperiodateIO
4
and orthoperiodateIO5−
6
.

See also

Related Research Articles

<span class="mw-page-title-main">Iodine</span> Chemical element with atomic number 53 (I)

Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at 114 °C (237 °F), and boils to a violet gas at 184 °C (363 °F). The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek Ιώδης, meaning 'violet'.

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

Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO4. The compound is noteworthy for its many uses, despite its toxicity and the rarity of osmium. It also has a number of unusual properties, one being that the solid is volatile. The compound is colourless, but most samples appear yellow. This is most likely due to the presence of the impurity OsO2, which is yellow-brown in colour. In biology, its property of binding to lipids has made it a widely-used stain in electron microscopy.

<span class="mw-page-title-main">Nitrogen dioxide</span> Chemical compound with formula NO₂

Nitrogen dioxide is a chemical compound with the formula NO2. One of several nitrogen oxides, nitrogen dioxide is a reddish-brown gas. It is a paramagnetic, bent molecule with C2v point group symmetry. Industrially, NO2 is an intermediate in the synthesis of nitric acid, millions of tons of which are produced each year, primarily for the production of fertilizers.

An iodide ion is the ion I. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual disability.

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

Dinitrogen pentoxide is the chemical compound with the formula N2O5. It is one of the binary nitrogen oxides, a family of compounds that only contain nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.

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

Dichlorine heptoxide is the chemical compound with the formula Cl2O7. This chlorine oxide is the anhydride of perchloric acid. It is produced by the careful distillation of perchloric acid in the presence of the dehydrating agent phosphorus pentoxide:

<span class="mw-page-title-main">Periodate</span> Negatively-charged molecule made of oxygen and iodine

Periodate is an anion composed of iodine and oxygen. It is one of a number of oxyanions of iodine and is the highest in the series, with iodine existing in oxidation state +7. Unlike other perhalogenates, such as perchlorate, it can exist in two forms: metaperiodateIO
4
and orthoperiodateIO5−
6
. In this regard it is comparable to the tellurate ion from the adjacent group. It can combine with a number of counter ions to form periodates, which may also be regarded as the salts of periodic acid.

<span class="mw-page-title-main">Periodic acid</span> Oxoacid of iodine (H5IO6 or HIO4)

Periodic acid is the highest oxoacid of iodine, in which the iodine exists in oxidation state +7. It can exist in two forms: orthoperiodic acid, with the chemical formula H5IO6, and metaperiodic acid, which has the formula HIO4.

Ruthenium tetroxide is the inorganic compound with the formula RuO4. It is a yellow volatile solid that melts near room temperature. It has the odor of ozone. Samples are typically black due to impurities. The analogous OsO4 is more widely used and better known. It is also the anhydride of hyperruthenic acid (H2RuO5). One of the few solvents in which RuO4 forms stable solutions is CCl4.

Osmium compounds are compounds containing the element osmium (Os). Osmium forms compounds with oxidation states ranging from −2 to +8. The most common oxidation states are +2, +3, +4, and +8. The +8 oxidation state is notable for being the highest attained by any chemical element aside from iridium's +9 and is encountered only in xenon, ruthenium, hassium, iridium, and plutonium. The oxidation states −1 and −2 represented by the two reactive compounds Na
2
[Os
4
(CO)
13
]
and Na
2
[Os(CO)
4
]
are used in the synthesis of osmium cluster compounds.

Iodine compounds are compounds containing the element iodine. Iodine can form compounds using multiple oxidation states. Iodine is quite reactive, but it is much less reactive than the other halogens. For example, while chlorine gas will halogenate carbon monoxide, nitric oxide, and sulfur dioxide, iodine will not do so. Furthermore, iodination of metals tends to result in lower oxidation states than chlorination or bromination; for example, rhenium metal reacts with chlorine to form rhenium hexachloride, but with bromine it forms only rhenium pentabromide and iodine can achieve only rhenium tetraiodide. By the same token, however, since iodine has the lowest ionisation energy among the halogens and is the most easily oxidised of them, it has a more significant cationic chemistry and its higher oxidation states are rather more stable than those of bromine and chlorine, for example in iodine heptafluoride.

Deoxygenation is a chemical reaction involving the removal of oxygen atoms from a molecule. The term also refers to the removal of molecular oxygen (O2) from gases and solvents, a step in air-free technique and gas purifiers. As applied to organic compounds, deoxygenation is a component of fuels production as well a type of reaction employed in organic synthesis, e.g. of pharmaceuticals.

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

Iodine pentoxide is the chemical compound with the formula I2O5. This iodine oxide is the anhydride of iodic acid, and one of the few iodine oxides that is stable. It is produced by dehydrating iodic acid at 200 °C in a stream of dry air:

Unlike its lighter congeners, the halogen iodine forms a number of stable organic compounds, in which iodine exhibits higher formal oxidation states than -1 or coordination number exceeding 1. These are the hypervalent organoiodines, often called iodanes after the IUPAC rule used to name them.

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

Tetraiodine nonoxide is an iodine oxide with the chemical formula I4O9.

<span class="mw-page-title-main">Lanthanum(III) iodide</span> Chemical compound

Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula LaI
3
.

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

Iodine monoxide is a binary inorganic compound of iodine and oxygen with the chemical formula IO•. A free radical, this compound is the simplest of many iodine oxides. It is similar to the oxygen monofluoride, chlorine monoxide and bromine monoxide radicals.

<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.

Diiodine tetraoxide, I2O4, is a chemical compound of oxygen and iodine. It belongs to the class of iodine oxides, and is a mixed oxide, consisting of iodine(III) and iodine(V) oxidation states.

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

Diiodine hexaoxide, is a chemical compound of oxygen and iodine with the chemical formula I2O6. It belongs to the class of iodine oxides, and is a mixed oxide, consisting of iodine(V) and iodine(VII) oxidation states.

References

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  6. Cambie, Richard C.; Hayward, Rodney C.; Lindsay, Barry G.; Phan, Alice I. T.; Rutledge, Peter S.; Woodgate, Paul D. (1976). "Reactions of iodine oxide with alkenes". Journal of the Chemical Society, Perkin Transactions 1 (18): 1961. doi:10.1039/P19760001961.
  7. Hoffmann, Thorsten; O'Dowd, Colin D.; Seinfeld, John H. (15 May 2001). "Iodine oxide homogeneous nucleation: An explanation for coastal new particle production" (PDF). Geophysical Research Letters. 28 (10): 1949–1952. Bibcode:2001GeoRL..28.1949H. doi: 10.1029/2000GL012399 .
  8. Carpenter, Lucy J.; MacDonald, Samantha M.; Shaw, Marvin D.; Kumar, Ravi; Saunders, Russell W.; Parthipan, Rajendran; Wilson, Julie; Plane, John M.C. (13 January 2013). "Atmospheric iodine levels influenced by seasurface emissions of inorganic iodine" (PDF). Nature Geoscience. 6 (2): 108–111. Bibcode:2013NatGe...6..108C. doi:10.1038/ngeo1687.
  9. Saiz-Lopez, A.; Fernandez, R. P.; Ordóñez, C.; Kinnison, D. E.; Gómez Martín, J. C.; Lamarque, J.-F.; Tilmes, S. (10 December 2014). "Iodine chemistry in the troposphere and its effect on ozone". Atmospheric Chemistry and Physics. 14 (23): 13119–13143. Bibcode:2014ACP....1413119S. doi: 10.5194/acp-14-13119-2014 . hdl: 11336/100317 .
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  11. Sunder, S.; Wren, J. C.; Vikis, A. C. (December 1985). "Raman spectra of I4O9 formed by the reaction of iodine with ozone". Journal of Raman Spectroscopy. 16 (6): 424–426. Bibcode:1985JRSp...16..424S. doi:10.1002/jrs.1250160611.