# Mechanism for reaction between aluminium and iodine

What should be a suitable mechanism for the reaction between aluminium and iodine, catalysed by water?

In my initial approaches, I had first thought of repeated attacks of the lone pairs of oxygen in water on aluminium, then formation of $\ce{Al(OH)3}$ by losing $\ce{H+}$, then $\ce{H+}$ attacking $\ce{I2}$, and formation of $\ce{HI}$, and finally formation of $\ce{AlI3}$.

But actually $\ce{Al2I6}$ is formed, so how can I accommodate its formation in that?

Is anything wrong in the above suggested mechanism? If the actual mechanism is something else, please write it in your answer.

A Lewis dot structure of the mechanism would be appreciated.

• There are a lot of problems in your proposed mechanism, which you would notice if you actually wrote the equations out. – DHMO Jan 24 '17 at 15:17
• The biggest problem is of course, my initially thought mechanism does not give me $\ce{Al2I6}$ , and that is why I asked this question. – Rohinb97 Jan 28 '17 at 12:43

$$\ce{2Al + 3I2 → 2AlI3}$$
The reaction is very exothermic and may burst into flame. The heat of the reaction will sublime the $\ce{I2}$ sending a deep purple fumes. The reaction is a general redox reaction. The aluminum is the reducing agent which gets oxidized by donating electrons and the iodine is the oxidizing agent which gets reduced by accepting electrons.
$$\ce{Al → Al^3+ + 3e–}$$
$$\ce{I2 + 2e^{–} → 2I^{–}}$$