When iron is heated in a low partial pressure of oxygen above 575°C,
FeO is formed. However, this is only stable at high temperatures and decomposes into iron
and Fe304 when it is cooled slowly. To obtain crystalline FeO the high temperature product
must be quenched rapidly to stop this disproportionation.
Crystalline FeO (wustite) melts at 1368°C with a heat of fusion ΔH= 7·5 kcal
mole-1. It has a heat of formation of - 63·7 kcal mole-1 at 25° and a density of 5·7. Below
198°K (the Néel temperature) FeO is antiferromagnetic. It crystallizes with the rock salt
structure having four Fe2+ and four02- ions per unit cell.
Black cubic crystal; density 5.7g/cm3; melts at 1,377°C; insoluble in water and alkalies; dissolves in acids.
Iron(II) oxide occurs in the mineral, wustite. It is used in the manufacture of heat-absorbing green glasses. It also is used in ceramic mixtures and enamels; and as a catalyst.
In manufacture of green, heat-absorbing glass; in steel manufacture; in enamels; as catalyst.
In manufacture of green, heat-absorbing glass; in steel manufacture; and as a catalystIron(II) oxide is used in manufacturing of green, heat-absorbing glass; in steel manufacture; and as a catalyst. It is used as a dye or pigment in pottery, glazes and glasses. It finds application as heat-absorbing glass used in buildings and automobiles. It is used as a precursor in the production of steel. It is also used in cosmetics and some tattoo inks. It can also be used for filtering phosphates from home aquaria and acts as a catalyst in a number of industrial and chemical operations.
ChEBI: Ferrous oxide is an iron oxide.
Iron(II) oxide may be prepared by thermal decomposition of iron(II) oxalate:
FeC2O4 → FeO + CO + CO2
The product obtained above is impure, that may contain small quantities of triiron tetroxide, Fe3O4 and carbon.
The oxide is stable above 575°C. Thus, it can be prepared by heating iron with oxygen under appropriate pressure at 575°C. Also, iron(II) oxide has been prepared by saturating the fused triiron tetroxide with iron, powdering the mixture, followed by magnetic separation of the oxide from excess iron (Sidgwick, N.V. 1950. The Chemical Elements and Their Compounds, Vol.2, pp 1328, Oxford: Clarendon Press).
