RADIATION CHEMISTRY OF ALKALI THIOSULFATES

Abstract

The salts Na2S2O3, Na2S2O3•5H2O, K2S2O3, and [Formula: see text] were irradiated at room temperature with 60Co gamma rays. When the irradiated salts were dissolved in water, sulfite and sulfate ions, H2S gas, colloidal sulfur, and a relatively small quantity of acid were found among the irradiation products. The dependence of yields on the absorbed dose was studied. G-values of approximately unity were found. Using 35S as a label, it was found that the inner sulfur (the central, oxygen-bonded sulfur atom of the complex) appears in the sulfite and sulfate whereas the outer sulfur (the sulfur linked only to the central sulfur and not to oxygen) appears in the H2S and colloidal sulfur. Annealing experiments using irradiated Na2S2O3 and K2S2O3 showed that the yields of sulfite, sulfate, and H2S were decreased by heating. The sodium salts were also irradiated at 77°K. The yields of sulfate and H2S were higher for the low temperature irradiations as compared to room temperature irradiations, whereas the yields of sulfite were lower. A tentative mechanism which partially explains the results is proposed.