Iron(II) oxide

Iron(II) oxide
Names
IUPAC name
Iron(II) oxide
Other names
Ferrous oxide,iron monoxide
Identifiers
1345-25-1 Yes
ChEBI CHEBI:50820 Yes
ChemSpider 14237 Yes
Jmol-3D images Image
PubChem 14945
UNII G7036X8B5H Yes
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
2.23
Hazards
MSDS ICSC 0793
Main hazards can be pyrophoric
EU Index Not listed
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g., sodium chloride Reactivity (yellow): no hazard code Special hazards (white): no codeNFPA 704 four-colored diamond
0
0
variable
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 noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Iron(II) 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, 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.[2]

Preparation

FeO can be prepared by the thermal decomposition of iron(II) oxalate.

FeC2O4 → FeO + CO2 + CO

The procedure is conducted a protective atmosphere to avoid the formation of ferric oxide. A similar procedure can also be used for the synthesis of manganous oxide and stannous oxide.[3][4]

Stoichiometric FeO can be prepared by heating Fe0.95O with metallic iron at 770 °C and 36 kbar.[5]

Reactions

FeO is thermodynamically unstable below 575 °C, tending to disproportionate to metal and Fe3O4:[2]

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.[5]

Below 200 K there is a minor change to the structure which changes the symmetry to rhombohedral and samples become antiferromagnetic.[5]

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.[6]

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 for filtering phosphates from home aquaria.

References

  1. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. ↑ 2.0 2.1 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419.
  3. ↑ 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.
  4. ↑ Practical Chemistry for Advanced Students, Arthur Sutcliffe, 1930 (1949 Ed.), John Murray - London
  5. ↑ 5.0 5.1 5.2 Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford University Press ISBN 0-19-855370-6
  6. ↑ Science Jan 2012

External links