The absorption spectra in a large range of concentrations show that the reactions of iodate
with iodine in 96% sulfuric acid produce (IO) HSO 4, I 3+ and I 5+, just like in the pure 100%
acid. We discovered that, in 96% H 2 SO 4, these reactions also produce I 2 O which is not
formed in the pure acid. I 2 O is an important intermediate of reactions in diluted sulfuric acid,
including the Bray-Liebhafsky reaction, but it had never been observed directly because of
its very high reactivity. The equilibrium constants of the reactions producing these four …