The spectrum and stability of oxygen iodide charge-transfer complex

Extra absorption spectra due to oxygen iodide charge-transfer interaction in different solvents were studied. Attempts to determine the stability constant of the O₂I^- complex led to an upper limit of K ≤ 0.3 M^-1. Heats of formation of 1.2,0.0, and -0.7 kcal in water, ethanol, and ethyleneglycol, respectively, wereobtained. From the solvent dependence of the optical absorption intensity and the heats of formation, an outer-sphere type oxygen iodide complex was proposed. From the energies of the optical transitions, a vertical electron affinity of E_O2^v < 5 kcal for oxygen was estimated.