Iron(II,III) oxide

• Triiron tetraoxide
• Magnetite ( mineral )

Deep black, ferromagnetic powder

Fixed

5.2 g · cm -3

1538 ° C

Insoluble in water

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Iron (II, III ) oxide is an oxide of iron, contains both two as trivalent iron. It has the chemical formula FeO · Fe2O3 or Fe3O4 and is therefore referred to as triiron tetraoxide. In nature it is found as magnetite. The melting point is 1538 ° C.

Representation

Made of iron and oxygen at very high temperatures:

Iron and steam at temperatures below 560 ° C.

Of iron (III ) oxide at temperatures above 1200 ° C.

Of iron (III ) oxide by reduction with hydrogen,

As an iron hammer or scale one called earlier the forging coming off of red-hot iron iron particles oxidized in the air immediately to Fe3O4.

Sintering is another name for the iron oxides, which arise in the continuous casting for the production of steel slabs and the hot rolling of steel. By the contact of hot steel with the oxygen formed on the surface of the slabs, iron oxides, which in addition to iron (III ) oxide containing a high proportion of magnetite.

Properties

Black, temperature-resistant, ferrimagnetic substance with spinel structure. Insoluble in water, acids and alkalis, but soluble in hydrofluoric acid.

Use

As the pigment, iron oxide black for temperature-resistant, black tones. As the magnetic pigment (magnetic pigment) for audio and video tapes.

One of the main applications is as a cheap catalyst with high life in the Haber- Bosch process for the synthesis of ammonia. Magnetite also serves as a catalyst component in the dehydrogenation of ethylbenzene to styrene.