Some common features of the action of UV light and gamma rays on hexacyanocobaltate(III) in aqueous solution

Spectrophotometric-cum-polarographic studies show that photolysis of [Cosup(III)(CN)sub(6)]sup(3-) with 254 nm light, which corresponds with a high energy d-d band of this ion and is at the tail of a CT band, causes photosubstitution as well as photoreduction, giving [Cosup(III)(CN)sub(5)Hsub(2)O]sup(2-) and [Cosup(II)(CN)sub(5)]sup(3-). With 202 nm light corresponding the CT band, only photoreduction to [Cosup(II)(CN)sub(5)]sup(3-) takes place. Radiolysis of neutral and acidic solutions of K3CO(CN)6 in the absence of dissolved oxygen gives both [Cosup(II)(CN)]sub(5)sup(3-) and [Cosup(III)(CN)sub(5)Hsub(2)O]sup(2-) and the absorption curves of the radiolysed solutions are similar to those of solutions photolysed with 254 nm light. In the case of air-saturated solutions, radiolysis gives only [Cosup(III)(CN)sub(5)Hsub(2)]Osup(2-) so long as dissolved oxygen is present, thereafter, both [Cosup(III)(CN)sub(5)Hsub(2)O]sup(2-) and [Cosup(II)(CN)sub(5)]sup(3-) are formed. Radiolysis with oxygen bubbling through the solution gives only [Cosup(III)(CN)sub(5)Hsub(2)O]sup(2-). Fair agreement has been found between observed G-values and those expected under the different conditions of radiolysis. (auth.)