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.

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

Aluminium reacts with iodine to form aluminium iodide. Water acts as catalyst.

$$\ce{2Al + 3I2 → 2AlI3}$$

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.

$$\ce{Al → Al^3+ + 3e–}$$

$$\ce{I2 + 2e^{–} → 2I^{–}}$$

  • 5
    $\begingroup$ This is entirely correct but doesn't answer the question because it doesn't say anything about the mechanism. Consider revising your answer or I will flag it for deletion. $\endgroup$ – bon May 6 '16 at 14:47
  • 1
    $\begingroup$ @bon The reaction has a redox type of mechanism and I think the reaction proceeds in this way. I am not able to find any source claiming the OP's mechanism despite many searchings... $\endgroup$ – Nilay Ghosh May 6 '16 at 15:17

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