Anhydrous transition-metal sulphites. Part II. Preparation of anhydrous cobalt(II) and nickel(II) sulphates and pyrosulphates by oxidation of anhydrous cobalt(II) and nickel(II) sulphites, using the mixed non-aqueous system dimethyl sulphoxide–sulphur dioxide

Abstract

Dimethyl sulphoxide in the presence of sulphur dioxide oxidizes anhydrous cobalt(II) and nickel(II) sulphites to the corresponding pyrosulphates, which are obtained as the crystalline dimethyl sulphoxide complexes, Co(dmso)₆S₂O₇ and Ni(dmso)₆S₂O₇. Thermal decomposition of the complexes leads to the formation of anhydrous cobalt(II) and nickel(II) pyrosulphates and anhydrous cobalt(II) and nickel(II) sulphates. The constitutions of the products have been investigated by analytical, spectroscopic, and magnetic techniques, and the mechanism of the oxidative process discussed.