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 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.

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.

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
 * 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 HI, which is corrosive. Lewis acids are skin irritants.