Aluminium iodide

Aluminium iodide
Preferred IUPAC name

Aluminium iodide
Other names

Aluminium(III) iodide

Aluminum iodide
Aluminium triiodide

Aluminum triiodide
Identifiers
CAS number 7784-23-8 (anhydrate), 10090-53-6 (hexahydrate)
PubChem 82222 (anhydrate) Y
ChemSpider 74202 (anhydrate) Y
EC number 232-054-8
UN number UN 3260
Jmol-3D images Image 1
Properties
Molecular formula AlI3
Molar mass 407.69495 g/mol (anhydrous)
515.786 g/mol (hexahydrate)
Appearance colorless powder
but impure samples
are often brown
Density 3.98 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 water reacts violently (anhydrous)
soluble (hexahydrate)
Solubility in alcohol, ether soluble (hexahydrate)
 Y (verify) (what is: Y/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. As for the related chloride and bromide, AlI3 is a strong Lewis acid and should be protected from the atmosphere.

Contents

Applications in organic synthesis

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

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 composition AlI is unstable at room temperature with respect 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

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

References

  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:10.1002/047084289. 
  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.