1.0 2010-04-08 22:08:43 UTC 2025-11-18 23:17:08 UTC FDB009630 Iron oxide Iron oxide, also known as eisen(ii)-oxid or ferrous oxide, is a member of the class of compounds known as transition metal oxides. Transition metal oxides are inorganic compounds containing an oxygen atom of an oxidation state of -2, in which the heaviest atom bonded to the oxygen is a transition metal. Iron oxide can be found in cocoa bean and common hazelnut, which makes iron oxide a potential biomarker for the consumption of these food products. Iron oxides and oxide-hydroxides are wide spread in nature, play an important role in many geological and biological processes, and are widely used by humans, e.g., as iron ores, pigments, catalysts, in thermite (see the diagram) and hemoglobin. Common rust is a form of iron(III) oxide. Iron oxides are widely used as inexpensive, durable pigments in paints, coatings and colored concretes. Colors commonly available are in the "earthy" end of the yellow/orange/red/brown/black range. When used as a food coloring, it has E number E172 . Ancor FR Ancor FY Eisen(II)-oxid FEO Ferrous oxide Gastromark Iron monooxide Iron monoxide Iron oxide (feo) Iron oxide, spent Iron oxide, synthetic Iron(2) oxide iron(2+) oxide Iron(II) oxide Lautamasse MIO 2F MIO 40GN Mio-KS NAT Natural wuestite Prodorite filler Se-DBS Siferrit FeO 71.844 71.929856755 oxoiron iron oxide 1332-37-2 O=[Fe] InChI=1S/Fe.O UQSXHKLRYXJYBZ-UHFFFAOYSA-N belongs to the class of inorganic compounds known as transition metal oxides. These are inorganic compounds containing an oxygen atom of an oxidation state of -2, in which the heaviest atom bonded to the oxygen is a transition metal. Transition metal oxides Inorganic compounds Mixed metal/non-metal compounds Transition metal organides Transition metal oxides Inorganic oxides Inorganic salts Inorganic oxide Inorganic salt Transition metal oxide iron oxide logp 0.049 ChemAxon pka_strongest_basic -0.21 ChemAxon iupac oxoiron ChemAxon average_mass 71.844 ChemAxon mono_mass 71.929856755 ChemAxon smiles O=[Fe] ChemAxon formula FeO ChemAxon inchi InChI=1S/Fe.O ChemAxon inchikey UQSXHKLRYXJYBZ-UHFFFAOYSA-N ChemAxon polar_surface_area 17.07 ChemAxon refractivity 1.44 ChemAxon polarizability 2.92 ChemAxon rotatable_bond_count 0 ChemAxon acceptor_count 1 ChemAxon donor_count 0 ChemAxon physiological_charge 0 ChemAxon formal_charge 0 ChemAxon Specdb::MsMs 1310476 Specdb::MsMs 1310477 Specdb::MsMs 1310478 50820 Cocoa bean Type 1 specific Theobroma cacao 3641 4.0 4.0 4.0 mg/100 g Common hazelnut Type 1 specific Corylus avellana 13451 237.6 237.6 237.6 mg/100 g