ABSTRACT
Iron is an abundant and environmentally friendly element. Iron
oxides are one of the most important functional materials used as
magnetic materials, catalysts, pigments, etc. For example, α-Fe2O3,
α-FeOOH, γ -Fe2O3, and Fe3O4 are used as red pigments, combustion
catalysts, toner of copying machines, magnetic recording medium
of video-tapes, and contrast agents for magnetic resonance imaging,
respectively.
