The reactions of the chromate, dichromate, and permanganate ions with 100% sulfuric acid and dilute oleum

Solutions of potassium chromate and potassium dichromate in 100% sulfuric acid and dilute oleum have been investigated by cryoscopic and conductimetric methods. It is shown that they both react to give the compound CrO2(HSO4)2. The absorption spectra of solutions of potassium chromate and dichromate in 100% sulfuric acid are very similar to the spectra of species of the type CrO2X2. Potassium permanganate dissolves in 100% sulfuric acid to give green solutions which are shown to contain MnO3•SO4H. The formation of this compound has been further confirmed by conductimetric measurements in dilute oleum. The absorption spectra of these green solutions are also consistent with the formation of a species of the type MnO3X.