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| Names | |
|---|---|
| IUPAC name Iron(II) oxide | |
| Other names Ferrous oxide, Iron monoxide, Wüstite | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
|
| ECHA InfoCard | 100.014.292 |
| 13590 | |
| UNII | |
| |
| |
| 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 inalkali,alcohol dissolves inacid |
| +7200×10−6 cm3/mol | |
Refractive index (nD) | 2.23 |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | can be combustible under specific conditions[2] |
| NFPA 704 (fire diamond) | |
| 200 °C (392 °F; 473 K) | |
| Safety data sheet (SDS) | ICSC 0793 |
| Related compounds | |
Otheranions | Iron(II) sulfide Iron(II) selenide Iron(II) telluride |
Othercations | Manganese(II) oxide Cobalt(II) oxide |
| Iron(II,III) oxide Iron(III) oxide | |
Related compounds | Iron(II) fluoride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Iron(II) oxide orferrous oxide is theinorganic compound with the formula FeO. Its mineral form is known aswüstite.[3][4] One of severaliron oxides, it is a black-colored powder that is sometimes confused withrust, the latter of which consists of hydratediron(III) oxide (ferric oxide). Iron(II) oxide also refers to a family of relatednon-stoichiometric compounds, which are typically iron deficient with compositions ranging from Fe0.84O to Fe0.95O.[5]
FeO can be prepared by the thermal decomposition ofiron(II) oxalate.
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 ofmanganous oxide andstannous oxide.[6][7]
Stoichiometric FeO can be prepared by heating Fe0.95O with metallic iron at 770 °C and 36 kbar.[8]
FeO is thermodynamically unstable below 575 °C, tending to disproportionate to metal andFe3O4:[5]
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.[8]
In contrast to the crystalline solid, in the molten state iron atoms are coordinated by predominantly 4 or 5 oxygen atoms.[9]
Below 200 K there is a minor change to the structure which changes the symmetry to rhombohedral and samples becomeantiferromagnetic.[8][10]
Iron(II) oxide makes up approximately 9% of the Earth'smantle. 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.[11]
Iron(II) oxide is used as apigment. It isFDA-approved for use in cosmetics and it is used in sometattoo inks. It can also be used as a phosphate remover from home aquaria.
