:Iron(II) oxide
{{short description|Inorganic compound with the formula FeO}}
{{Chembox
| Watchedfields = changed
| verifiedrevid = 477163416
| ImageFile1 = Iron(II) oxide.jpg
| ImageSize1 =
| ImageName1 = Iron(II) oxide
| ImageFile2 = Manganese(II)-oxide-xtal-3D-SF.png
| ImageSize2 =
| IUPACName = Iron(II) oxide
| SystematicName =
| OtherNames = Ferrous oxide, Iron monoxide, Wüstite
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 14237
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = G7036X8B5H
| InChI = 1/Fe.O/rFeO/c1-2
| InChIKey = UQSXHKLRYXJYBZ-WPTVXXAFAB
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 50820
| SMILES = [Fe]=O
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/Fe.O
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = UQSXHKLRYXJYBZ-UHFFFAOYSA-N
| CASNo = 1345-25-1
| CASNo_Ref = {{cascite|correct|CAS}}
| EINECS =
| PubChem = 14945
| RTECS =
| Gmelin = 13590
}}
| Section2 = {{Chembox Properties
| Formula = FeO
| MolarMass = 71.844 g/mol
| Appearance = black crystals
| Density = 5.745 g/cm3
| MeltingPtC = 1377
| MeltingPt_ref = Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}
| BoilingPtC = 3414
| BoilingPt_notes =
| Solubility = Insoluble
| SolubleOther = insoluble in alkali, alcohol
dissolves in acid
| Solvent =
| pKa =
| pKb =
| RefractIndex = 2.23
| MagSus = {{val|+7200|e=-6|u=cm3/mol}}
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| Section3 = {{Chembox Structure
| CrystalStruct =
| Coordination =
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| Section4 = {{Chembox Thermochemistry
| DeltaHf =
| DeltaHc =
| Entropy =
| HeatCapacity =
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| Section7 = {{Chembox Hazards
| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0793.htm ICSC 0793]
| MainHazards = can be combustible under specific conditions{{Cite web|url=https://art.illinois.edu/images/documents/MSDS/Metals/Ferric-Oxide.pdf|title=Ferric(ous) Oxide, Black |website=art.illinois.edu |archive-url=https://web.archive.org/web/20190511223604/https://art.illinois.edu/images/documents/MSDS/Metals/Ferric-Oxide.pdf |archive-date=11 May 2019 |url-status=dead}}
| NFPA-H = 1
| NFPA-F = 1
| NFPA-R = 0
| FlashPt =
| AutoignitionPtC = 200
| ExploLimits =
| PEL =
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| Section8 = {{Chembox Related
| OtherAnions = Iron(II) sulfide
Iron(II) selenide
Iron(II) telluride
| OtherCations = Manganese(II) oxide
Cobalt(II) oxide
| OtherFunction = Iron(II,III) oxide
Iron(III) oxide
| OtherFunction_label = Iron oxides
| OtherCompounds = Iron(II) fluoride
}}
}}
Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite.{{Cite web|url=https://www.mindat.org/min-4316.html|title=Wüstite|website=www.mindat.org}}{{Cite web|url=https://www.ima-mineralogy.org/Minlist.htm|title=List of Minerals|date=March 21, 2011|website=www.ima-mineralogy.org}} 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.{{Greenwood&Earnshaw}}
Preparation
FeO can be prepared by the thermal decomposition of iron(II) oxalate.
:{{chem2|FeC2O4 -> FeO + CO2 + CO}}
The procedure is conducted under an inert atmosphere to avoid the formation of iron(III) oxide ({{chem2|Fe2O3}}). A similar procedure can also be used for the synthesis of manganous oxide and stannous oxide.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
Stoichiometric FeO can be prepared by heating Fe0.95O with metallic iron at 770 °C and 36 kbar.Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford University Press {{ISBN|0-19-855370-6}}
Reactions
FeO is thermodynamically unstable below 575 °C, tending to disproportionate to metal and Fe3O4:
:{{chem2|4 FeO -> 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.
In contrast to the crystalline solid, in the molten state iron atoms are coordinated by predominantly 4 or 5 oxygen atoms.{{cite journal |last1=Shi |first1=Caijuan |last2=Alderman |first2=Oliver |last3=Tamalonis |first3=Anthony |last4=Weber |first4=Richard |last5=You |first5=Jinglin |last6=Benmore |first6=Chris |title=Redox-structure dependence of molten iron oxides |journal=Communications Materials |date=2020 |volume=1 |issue=1 |page=80 |doi=10.1038/s43246-020-00080-4 |bibcode=2020CoMat...1...80S |doi-access=free }}
Below 200 K there is a minor change to the structure which changes the symmetry to rhombohedral and samples become antiferromagnetic.{{Cite book |date=2017 |title= Proceedings of the 5th Unconventional Resources Technology Conference|url=http://dx.doi.org/10.15530/urtec-2017-2670073 |location=Tulsa, OK, USA |publisher=American Association of Petroleum Geologists |doi=10.15530/urtec-2017-2670073|isbn= 978-0-9912144-4-0}}
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.{{Cite web|url=http://news.sciencemag.org/sciencenow/2012/01/electric-material-in-mantle-coul.html?ref=hp|archiveurl=https://web.archive.org/web/20120124011327/http://news.sciencemag.org/sciencenow/2012/01/electric-material-in-mantle-coul.html?ref=hp|url-status=dead|title=Science Jan 2012|archivedate=January 24, 2012}}
Uses
See also
References
{{reflist}}
External links
- [http://webmineral.com/data/Wustite.shtml Wustite Mineral Data]
{{Iron compounds}}
{{Oxides}}
{{Molecules detected in outer space}}
{{oxygen compounds}}
Category:Non-stoichiometric compounds
Category:Transition metal oxides