The iron corrosion process in water at room temperature was followed by observing changes in crystal morphology, crystal lattices and diffraction patterns of the products by high resolution electron microscopy. The rate of oxidation of green rust, formed at the initial stages of the corrosion processes, determines the nature of the oxides and oxyhydroxides formed on the iron surface. In solution, the morphology of crystalline gamma-FeOOH and its transformation to alphaFeOOH was dependent on the OH_- concentration and the duration of reaction. -- AATA