Spectrophotometric study of the solvation of iodine in dioxan solution

The solvation of iodine in dioxan‐carbon tetrachloride solutions was studied by determining a large number of absorption spectra at different compositions and different temperatures. The concentration of the iodine‐dioxan complex was derived from the extinction at 4515 Å (at 17° C), the wavelength of maximal absorption of iodine in pure dioxan, as compared with the extinction of iodine in pure dioxan and in pure carbon tetrachloride, respectively. Application of the mass law resulted in equilibrium constants essentially independent of concentration. However, this was only the case when based on the assumption of a ratio of 1:1 for the composition of the complex. From the dependance on temperature the heat of formation of the complex was found to be 2700 cal/mol.