Answer:
Iodine. The reaction between hot iron and iodine vapor produces gray iron(II) iodide, and is much less vigorous. This reaction, the equation for which is given below, is difficult to carry out because he product is always contaminated with iodine. Iodine is only capable of oxidizing iron to the +2 oxidation state.
I believe that it could happen.
2 BN(s) + 3 Cl2(g) = 2 BCl3(g) + N2(g)
Number 3 breaks down into smaller pieces
