Formation of Fe(II)1Fe(III)1 intermediate green complex on oxidation of ferrous ion in neutral and slightly alkaline sulphate solutions

The formation of Fe(II)Fe(III)-intermediate green complex in aqueous solutions has been investigated. From the u.v. absorption spectra and the chemical analysis of neutral and slightly alkaline sulphate solutions of 5 × 10 −4 – 7 × 10 −4 mole/l iron at different pH's, the complex Fe(II) 1 Fe(III) 1 was found with the progress of aerial oxidation of Fe(II) species corresponding to FeOH + . The result has been used to estimate the iron composition of solid-green rust II. The participation of the green complex and green rust in the formation of Fe 3 O 4 and γ-FeOOH in corrosion process of iron in aqueous solutions was briefly discussed.