rautaIIIIIoksidi

Rauta(III)oksidi, commonly known as iron(III) oxide, is an inorganic compound with the chemical formula Fe2O3. It occurs naturally as the mineral hematite and is a major iron ore. It has long been used as a red pigment (red ochre) and in various industrial processes.

Forms: The most stable phase is α-Fe2O3, hematite. A ferrimagnetic form γ-Fe2O3, maghemite, occurs as nanoparticles and is used in magnetic materials. All forms are oxides of iron in the +3 oxidation state.

Occurrence and production: Hematite ores are mined and processed to extract iron, which is then smelted to produce metallic iron and steel. Fe2O3 can also be synthesized by oxidizing iron metal or by thermal decomposition of iron(III) salts.

Properties: It is a dense, red-brown solid with a high melting point of about 1565°C. It is insoluble in water and relatively resistant to acids. Natural hematite varies in color from red to black and often shows a metallic to earthy luster. The magnetic behavior depends on the phase, with maghemite being ferrimagnetic and hematite typically weakly magnetic.

Applications: The primary use is as an iron ore in steelmaking. It is also widely used as a pigment in paints, coatings, and cosmetics. In nanotechnology, γ-Fe2O3 nanoparticles are employed in magnetic materials and catalysis.

Safety: Inhalation of iron oxide dust can irritate the respiratory tract; overall toxicity is considered low, though dust hazards are managed in mining and processing operations.