Iron(III) oxide

Iron(III) oxide, CAS 1309-37-1, is an inorganic iron compound commercially known as rouge, rubigo, ferrugo, and deanox. Approved as food colourant E172(ii) in the EU, it occurs naturally as the mineral hematite and is produced synthetically for industrial applications requiring consistent purity and particle size.

In coatings and primers, iron(III) oxide acts as a corrosion-inhibiting pigment by forming a passive barrier that limits oxygen and moisture contact with metal substrates. In construction materials such as concrete and paving, it provides UV-stable red-to-brown colouration. The automotive and printing sectors use it as a surface modifier to improve adhesion between layers.

Iron(III) oxide is sourced in natural ore and synthetic grades, with synthetic material meeting E172, FCC, and REACH compliance requirements. It is available as powder or lump form depending on application. Suppliers typically offer technical, food, and cosmetic grades with corresponding documentation for EU market entry.