Diiodine tetroxide

Last updated
Diiodine tetroxide [1]
Names
IUPAC name
iodosyl iodate
Identifiers
3D model (JSmol)
PubChem CID
  • InChI=1S/I2O4/c3-1-6-2(4)5
    Key: XHTWXUOEQMOFEJ-UHFFFAOYSA-N
  • O=IOI(=O)=O
Properties
I2O4
Molar mass 317.805 g·mol−1
Density 2.57
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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.

Contents

Synthesis

The oxide is formed by the reaction of hot concentrated sulfuric acid on iodic acid for several days. [2]

3HIO3 → I2O4 + HIO4 + H2O

It is formed from diiodine pentoxide and iodine in concentrated sulfuric acid or iodosyl sulfate (IO)2SO4 added to water: [3]

4(IO)2SO4 + 4H2O → I2O4 + I2 + 4H2SO4

Alternatively, excess of concentrated nitric acid oxidizes dry iodine to this salt. [4]

Physical properties

Diiodine tetraoxide is a yellow, granular powder. At temperatures above 85 °C it decomposes to diiodine pentoxide and iodine: [2]

5I2O4 → 4I2O5 + I2

This process is even faster at 135 °C. It dissolves in hot water to form iodate and iodide. [2] Structurally, the compound is an iodyl iodite O2I-OIO (iodine(V,III) oxide) [2] with bent IVO2 units (I–O distances 1.80 and 1.85 Å; ∠OIO angle 97°) and bent IIIIO2 units (IO distances 1.93 Å, OIO angle 95.8°). Both units are linked via I—O—I bridges to form polymeric zigzag chains (I2O4)x. [2]

Diiodine tetraoxide has a monoclinic crystal structure with the space group P21/c (space group number 14). Unit cell dimensions are a = 8.483 b = 6.696 c = 8.333 Å and β = 124.69°. Unit cell volume = 389.15 Å3. Z = 4. Density is 2.57 Mg/m3 [3] [5]

Reactions

Diiodine tetroxide oxidises hydrochloric acid: [6]

I2O4 + 8H+ + 8Cl → 2ICl + 4H2O + 3Cl2

It decomposes[ vague ] in water. [4] [7]

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'.

Sulfur trioxide (alternative spelling sulphur trioxide) is the chemical compound with the formula SO3. It has been described as "unquestionably the most [economically] important sulfur oxide". It is prepared on an industrial scale as a precursor to sulfuric acid.

<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 contain only nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.

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.

<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">Iodic acid</span> Chemical compound (HIO3)

Iodic acid is a white water-soluble solid with the chemical formula HIO3. Its robustness contrasts with the instability of chloric acid and bromic acid. Iodic acid features iodine in the oxidation state +5 and is one of the most stable oxo-acids of the halogens. When heated, samples dehydrate to give iodine pentoxide. On further heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.

<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.

Selenic acid is the inorganic compound with the formula H2SeO4. It is an oxoacid of selenium, and its structure is more accurately described as O2Se(OH)2. It is a colorless compound. Although it has few uses, one of its salts, sodium selenate is used in the production of glass and animal feeds.

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.

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

Thiocyanogen, (SCN)2, is a pseudohalogen derived from the pseudohalide thiocyanate, [SCN], with behavior intermediate between dibromine and diiodine. This hexatomic compound exhibits C2 point group symmetry and has the connectivity NCS-SCN.

<span class="mw-page-title-main">Iodine oxide</span> Class of chemical compounds

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.

<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:

A sulfite sulfate is a chemical compound that contains both sulfite and sulfate anions [SO3]2− [SO4]2−. These compounds were discovered in the 1980s as calcium and rare earth element salts. Minerals in this class were later discovered. Minerals may have sulfite as an essential component, or have it substituted for another anion as in alloriite. The related ions [O3SOSO2]2− and [(O2SO)2SO2]2− may be produced in a reaction between sulfur dioxide and sulfate and exist in the solid form as tetramethyl ammonium salts. They have a significant partial pressure of sulfur dioxide.

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

Praseodymium(III) iodide is an inorganic salt, consisting of the rare-earth metal praseodymium and iodine, with the chemical formula PrI3. It forms green crystals. It is soluble in water.

<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">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.

<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.

Diiodosyl sulfate is an inorganic compound, a basic salt of iodine and sulfuric acid with the formula (IO)2SO4. It forms yellow crystals.

Iodine sulfate is an inorganic compound with the formula I2(SO4)3. It appears as light yellow crystals and reacts with water.

References

  1. William M. Haynes, ed. (2014). CRC Handbook of Chemistry and Physics. CRC Press. p. S.4-67. ISBN   978-1482208689.
  2. 1 2 3 4 5 Holleman-Wiberg inorganic chemistry. San Diego, Calif. London: Academic. 2001. pp. 465–466. ISBN   0123526515.
  3. 1 2 Fjellvåg, Helmer; Kjekshus, Arne; Persson, Ingmar; Figgis, Brian N.; Liaaen-Jensen, Synnøve; Balzarini, Jan; Fransson, Bengt; Ragnarsson, Ulf; Francis, George W. (1994). "The Crystal Structure of I2O4 and its Relations to Other Iodine--Oxygen-Containing Compounds". Acta Chemica Scandinavica. 48: 815–822. doi: 10.3891/acta.chem.scand.48-0815 .
  4. 1 2 Holmyard, E. J. (1931). Inorganic Chemistry. Edward Arnold & Co. p. 521. ISBN   978-5-87636-953-6 . Retrieved 10 May 2023.
  5. Wu, Zhongqing; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya (28 May 2011). "First-principles calculations of the structural and dynamic properties, and the equation of state of crystalline iodine oxides I2O4, I2O5, and I2O6". The Journal of Chemical Physics. 134 (20). doi:10.1063/1.3590278. PMID   21639450.
  6. Advances in Inorganic Chemistry and Radiochemistry. Academic Press. 1 January 1963. p. 77-78. ISBN   978-0-08-057854-5.
  7. Perry, Dale L. (19 April 2016). Handbook of Inorganic Compounds. CRC Press. p. 210. ISBN   978-1-4398-1462-8 . Retrieved 10 May 2023.