Article révisé par les pairs
Résumé : The absorption spectra in a large range of concentrations show that the reactions of iodate with iodine in 96% sulfuric acid produce (IO)HSO4, I3+ and I5+, just like in the pure 100% acid. We discovered that, in 96% H2SO4, these reactions also produce I2O which is not formed in the pure acid. I2O 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 compounds were determined.