RADIATION CHEMISTRY OF ALKALI THIOSULFATES

The salts Na 2 S 2 O 3 , Na 2 S 2 O 3 •5H 2 O, K 2 S 2 O 3 , and [Formula: see text] were irradiated at room temperature with 60 Co gamma rays. When the irradiated salts were dissolved in water, sulfite and sulfate ions, H 2 S 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 35 S 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 H 2 S and colloidal sulfur. Annealing experiments using irradiated Na 2 S 2 O 3 and K 2 S 2 O 3 showed that the yields of sulfite, sulfate, and H 2 S were decreased by heating. The sodium salts were also irradiated at 77°K. The yields of sulfate and H 2 S 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.