Formation spectra and some chemical properties of oxydiodine radicals in aqueous solutions

The reactions of the hydrated electrons (eaq−) and OH radicals (generated by the interaction of fast electrons with water) with IO3− and IO− have been investigated by the pulse radiolysis technique. Absorption spectra of the transient species producted in the range 250–800 nm, have been obtained. IO2 formed by the reaction: IO3−+eaq−→IO2+2OH−, k1=7.7× 109M−1·sec−1 has a maximum absorption at 490 nm (e490=1.5× 103M−1·cm−1). No evidence was found for an absorption band at λmax=715 nm as previously claimed for this species. The transient absorbing species at λmax=360 nm (e360=8.0× 102M−1·cm−1) formed by the reaction of OH radicals and IO3−, is probably (IO3)2−, e.g., IO3−+OH→IO3+OH−, k2=1.7× 107M−1·sec−1, IO3+IO3−⇄(IO3)2−, K3=23M−1. In I−+IO− alkaline solutions two transient absorption bands at 370 and 700 nm are formed which decay at the identical rate (8× 109M−1·sec−1). This and the fact that in I− alkaline solutions the same spectrum was observed indicate that the band at 700 nm is also due to I2−. The de...