Characterization of Formation of Ferrous and Ferric Oxides in Aqueous Solution from a Multidisciplinary Viewpoint

This article reviews investigations on the formation of inhomogeneous ferrous (FeII) and ferric (FeIII) oxides in aqueous solution. These globally abundant materials are important extensive fields research including corrosion steels, mineralogy, environmental remediation, biochemistry. Iron polycations consisting FeII FeIII ions bridged by hydroxyl groups oxyanions. Solution conditions such as pH, temperature, presence foreign ions, oxygen markedly influence composition structure iron their transformation into various forms. Redox reactions great importance controlling extent conversion between forms resulting isolated species. Electrochemical potential versus pH (E–pH) diagrams particularly useful considering details oxide speciation a function solution conditions. Analytical techniques Mössbauer spectroscopy, X-ray diffraction, electron microscopy used to characterize morphology iron-oxide samples. The involvement mixed-valent (FeII/FeIII) species known green rusts (GRs) common is described terms oxidation level, ion content solutions. terrestrial origin possible role abiogenesis organisms also described. Despite inhomogeneity, varied components many natural industrial processes.