Iron(II) oxide

Ferrous

Black powder

Fixed

5.75 g · cm -3

1369 ° C

Insoluble in water

Attention

1.5 mg · m-3

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( Formerly known as ferrous oxide ) iron (II ) oxide is a chemical compound of iron and oxygen and is one of the oxides. Iron (II ) oxide is not normally set up stoichiometrically, the composition is about Fe0, Fe0 to 84O, 95O. This is due to the similar crystal structure of iron ( III ) oxide and that crystal defects are entropically favorable.

Occurrence

Iron (II ) oxide occurs during the process of the fresh / LD process ( reduction of the carbon content ) in the steel. Here, oxygen is blown into the molten iron. The oxygen combines with the iron to FeO, which in turn acts as an oxidizing agent for interfering foreign elements such as silicon, manganese and phosphorus:

By means of calcium oxide ( CaO), these oxides can be separated from the iron melt.

In nature, iron ( II) oxide is present as mineral wustite.

Production and representation

Iron (II ) oxide produced in the reduction of iron ( III) oxide with hydrogen or carbon monoxide. By oxidation of iron with a low oxygen pressure, or with water vapor at temperatures above 560 ° C can be iron ( II) oxide gain.

Stoichiometric iron (II ) oxide can be produced at room temperature by heating iron (II ) oxalate at about 850 ° C in vacuum and subsequent rapid quenching.

Furthermore, the stoichiometric iron ( II) oxide forms in the reaction of Fe 1 -x O, and iron at 770 ° C and 50 kilobars pressure of oxygen.

Properties

Iron (II ) oxide is only stable above 560 ° C. Below this temperature down to 300 ° C, it tends to disproportionate to iron and iron ( II, III ) oxide:

At room temperature is metastable. It can be easily oxidized, obtained by pyrolysis of the oxalate finely divided FeO is pyrophoric.

Iron (II ) oxide is antiferromagnetic with a Néel temperature of 198 K.

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