The article discusses the possible mechanisms of anodic formation of oxide compounds (by the example of Co2O3) and the relevant phase transformations during electrolysis in an aqueous solution of cobalt sulfate on the basis of an analysis of scientific papers and experimental data. The mechanism of anodic for mation of Co2O3 molecules with the involvement of adsorbed oxygen and phase formation processes taking into account the volumetric structure of the oxide molecules is proposed. The surface morphology of the investigated sediments proves that they are built up by means of step growth of crystals and the formation of large sized crystal grains displaying a certain tendency for spheroidization. Based on the Gibbs–Thompson equation for the electrochemical system, which correlates the value of the electrode potential with the radius and specific free surface energy of the nucleus, the possible energy relations of anodic nucleation of metal oxide compound are considered.