Aluminium iodide

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Aluminium iodide
Identifiers
CAS number7784-23-8 (anhydrate), 10090-53-6 (hexahydrate)
PubChem82222 (anhydrate) YesY
ChemSpider74202 (anhydrate) YesY
EC number232-054-8
UN numberUN 3260
Jmol-3D imagesImage 1
Properties
Molecular formulaAlI3
Molar mass407.69495 g/mol (anhydrous)
515.786 g/mol (hexahydrate)
Appearancecolorless powder
but impure samples
are often brown
Density3.98 g/cm3 (anhydrous)
2.63 g/cm3 (hexahydrate)
Melting point

189.4 °C (anhydrous)
185 °C, decomp. (hexahydrate)

Boiling point

360 °C, sublimes

Solubility in waterreacts violently (anhydrous)
soluble (hexahydrate)
Solubility in alcohol, ethersoluble (hexahydrate)
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
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Aluminium iodide
Identifiers
CAS number7784-23-8 (anhydrate), 10090-53-6 (hexahydrate)
PubChem82222 (anhydrate) YesY
ChemSpider74202 (anhydrate) YesY
EC number232-054-8
UN numberUN 3260
Jmol-3D imagesImage 1
Properties
Molecular formulaAlI3
Molar mass407.69495 g/mol (anhydrous)
515.786 g/mol (hexahydrate)
Appearancecolorless powder
but impure samples
are often brown
Density3.98 g/cm3 (anhydrous)
2.63 g/cm3 (hexahydrate)
Melting point

189.4 °C (anhydrous)
185 °C, decomp. (hexahydrate)

Boiling point

360 °C, sublimes

Solubility in waterreacts violently (anhydrous)
soluble (hexahydrate)
Solubility in alcohol, ethersoluble (hexahydrate)
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Aluminium iodide is any chemical compound containing only aluminium and iodine. Invariably, the name refers to a compound of the composition AlI3, formed by the reaction of aluminium and iodine[1] or the action of HI on Al metal. The hexahydrate is obtained from a reaction between metallic aluminum or aluminum hydroxide with hydrogen iodide or hydroiodic acid. Like the related chloride and bromide, AlI3 is a strong Lewis acid and should be protected from the atmosphere.

Applications in organic synthesis[edit source | edit]

Aluminium iodide is employed as a catalyst to break certain kinds of C-O and N-O bonds. It cleaves aryl ethers and deoxygenates epoxides.[2]

Aluminium(I) iodide[edit source | edit]

The name "aluminium iodide" is widely assumed to describe the triiodide or its dimer. In fact, a monoiodide also enjoys a role in the Al-I system, although the compound AlI is unstable at room temperature relative to the triiodide[3]

3 AlI → AlI3 + 2 Al

An illustrative derivative of aluminium monoiodide is the cyclic adduct formed with triethylamine, AI4I4(NEt3)4.

Safety[edit source | edit]

Hydrolysis of aluminium triiodide will release some HI, which is corrosive. Lewis acids are skin irritants.

References[edit source | edit]

  1. ^ G. W. Watt, J. L. Hall (1953). Inorganic Syntheses IV. pp. 117–119. 
  2. ^ M. Gugelchuk (2004). Aluminum Iodide, in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette). New York: J. Wiley & Sons. doi:10.1002/047084289X.ra083. 
  3. ^ Dohmeier, C.; Loos, D.; Schnöckel, H. (1996). "Aluminum(I) and Gallium(I) Compounds: Syntheses, Structures, and Reactions". Angewandte Chemie International Edition 35: 129–149. doi:10.1002/anie.199601291.