Molten potassium pyrosulfate: the reactions of 12 alkali-metal halides

The oxidation-reduction reactions of 12 alkali-metal halides with molten potassium pyrosulfate were studied. Chlorides, bromides and iodides of sodium, potassium, rubidium and caesium were found to be oxidized to produce chlorine, bromine and iodine respectively. Sulfur dioxide was found to be the main reduction product. The reactions between chlorides and pyrosulfate were slow and incomplete, whereas reactions of bromides and iodides were fast and complete. The order of the oxidizability (reducing power) of the halides by pyrosulfate, the temperatures, and stoichiometries of the reactions have been determined.