Aluminium iodide

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. As for the related chloride and bromide, AlI₃ is a strong Lewis acid and should be protected from the atmosphere.

Additional recommended knowledge

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Applications in organic synthesis

Aluminium iodide is employed 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]

6 AlI → Al₂I₆ + 4 Al

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

Safety

Hydrolysis aluminium triiodide will release some funky smells, which are corrosive. Lewis acids are skin irritants.

References

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