Electronic Spectrum of IO⁻ in Solution

Abstract

COMPOUNDS of iodine in the +1 oxidation state are unstable in aqueous solution, and for this reason their chemistry is still not clearly defined. Recording the absorption spectrum of IO⁻ should be helpful for a systematic investigation of this group. Conflicting reports have been published on this subject^1,2. Apart from the instability of IO⁻, the main difficulty arises from the overlap of its spectrum with that of other iodine compounds, in particular that of ${\text{I}}_{{\text{3}}^{-}}$. High alkalinity and low I⁻ concentration are desirable for suppressing the formation of ${\text{I}}_{{\text{3}}^{-}}$ and other +1 iodine compounds as HIO, I₂OH⁻ I₂O = (ref. 1). Here we report the results of a spectrophotometric examination of iodine in highly concentrated alkali solutions.