1. any of a group of nonmetallic, ceramiclike, usually ferromagnetic compounds of ferric oxide with other oxides, especially such a compound characterized by extremely high electrical resistivity and used in computer memory elements, permanent magnets, and various solid-state devices. also called ferrate.
2. iron that has not combined with carbon, occurring commonly in steel, cast iron, and pig iron below 910°C.

1. the interstitial solid solution of carbon in body-centered cubic iron
2. any of a class of metal oxides which show ferrimagnetism; used in transformers, inductors, antennas, recording heads, microwave devices, motors and loudspeakers
3. the anion FeO22-, and any of the salts (formally derived from the unknown ferrous acid) derived from it

1. A term proposed by Vogelsang to include indeterminable mineral substances of a reddish color, frequently observed in certain igneous rocks when they are examined in thin sections under the microscope. they probably consist in most cases of hydrous oxid of iron.
2. in chem.: A compound of ferric oxid (Fe2O3) with a more basic metallic oxid, as calcium ferrite (CaFe2O4), from the union of ferric oxid with lime (cao). the mineral franklinite consists essentially of zinc ferrite, and magnetite or magnetic iron ore (Fe3O4) may be viewed as iron ferrite (FeO.Fe2O3).
3. pure iron as separated out (from iron carbides) in the cooling of steel.

1. a solid solution in which alpha iron is the solvent