Iron(II) oxide
Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists of hydrated iron(III) oxide (ferric oxide). Iron(II) oxide also refers to a family of related non-stoichiometric compounds, which are typically iron deficient with compositions ranging from Fe0.84O to Fe0.95O.[3]
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| Names | |
|---|---|
| IUPAC name
Iron(II) oxide | |
| Other names
Ferrous oxide,iron monoxide | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.014.292 |
| 13590 | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| FeO | |
| Molar mass | 71.844 g/mol |
| Appearance | black crystals |
| Density | 5.745 g/cm3 |
| Melting point | 1,377 °C (2,511 °F; 1,650 K)[1] |
| Boiling point | 3,414 °C (6,177 °F; 3,687 K) |
| Insoluble | |
| Solubility | insoluble in alkali, alcohol dissolves in acid |
| +7200·10−6 cm3/mol | |
Refractive index (nD) |
2.23 |
| Hazards | |
| Main hazards | can be combustible under specific conditions[2] |
| Safety data sheet | ICSC 0793 |
| NFPA 704 (fire diamond) | |
| 200 °C | |
| Related compounds | |
Other anions |
iron(II) fluoride, iron(II) sulfide, iron(II) selenide, iron(II) telluride |
Other cations |
manganese(II) oxide, cobalt(II) oxide |
Related compounds |
Iron(III) oxide, Iron(II,III) oxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Preparation
FeO can be prepared by the thermal decomposition of iron(II) oxalate.
- FeC2O4 → FeO + CO2 + CO
The procedure is conducted under an inert atmosphere to avoid the formation of iron(III) oxide (Fe2O3). A similar procedure can also be used for the synthesis of manganous oxide and stannous oxide.[4][5]
Stoichiometric FeO can be prepared by heating Fe0.95O with metallic iron at 770 °C and 36 kbar.[6]
Reactions
FeO is thermodynamically unstable below 575 °C, tending to disproportionate to metal and Fe3O4:[3]
- 4FeO → Fe + Fe3O4
Structure
Iron(II) oxide adopts the cubic, rock salt structure, where iron atoms are octahedrally coordinated by oxygen atoms and the oxygen atoms octahedrally coordinated by iron atoms. The non-stoichiometry occurs because of the ease of oxidation of FeII to FeIII effectively replacing a small portion of FeII with two thirds their number of FeIII, which take up tetrahedral positions in the close packed oxide lattice.[6]
Below 200 K there is a minor change to the structure which changes the symmetry to rhombohedral and samples become antiferromagnetic.[6]
Occurrence in nature
Iron(II) oxide makes up approximately 9% of the Earth's mantle. Within the mantle, it may be electrically conductive, which is a possible explanation for perturbations in Earth's rotation not accounted for by accepted models of the mantle's properties.[7]
Uses
Iron(II) oxide is used as a pigment. It is FDA-approved for use in cosmetics and it is used in some tattoo inks. It can also be used as a phosphate remover from home aquaria.
See also
References
- Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
- https://art.illinois.edu/images/documents/MSDS/Metals/Ferric-Oxide.pdf
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- H. Lux "Iron (II) Oxide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1497.
- Practical Chemistry for Advanced Students, Arthur Sutcliffe, 1930 (1949 Ed.), John Murray - London
- Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford University Press ISBN 0-19-855370-6
- Science Jan 2012 Archived January 24, 2012, at the Wayback Machine
