| Names | |
|---|---|
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IUPAC name
pentacarbonyliron
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| Other names
Pentacarbonyl iron
Iron carbonyl |
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| Identifiers | |
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3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.033.323 |
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PubChem CID
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| RTECS number | NO4900000 |
| UNII | |
| UN number | 1994 |
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| Properties | |
| Fe(CO)5 | |
| Molar mass | 195.90 g/mol |
| Appearance | straw-yellow liquid |
| Odor | musty |
| Density | 1.453 g/cm3 |
| Melting point | −21.0 °C (−5.8 °F; 252.2 K) |
| Boiling point | 103 °C (217 °F; 376 K) |
| Insoluble | |
| Solubility | Soluble in organic solvents slightly soluble in alcohol insoluble in ammonia |
| Vapor pressure | 40 mmHg (30.6 °C) |
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Refractive index (nD)
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1.5196 (20 °C) |
| Structure | |
| D3h | |
| trigonal bipyramidal | |
| trigonal bipyramidal | |
| 0 D | |
| Hazards | |
| Main hazards | Very toxic, highly flammable |
| Safety data sheet | ICSC 0168 |
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EU classification (DSD) (outdated)
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| NFPA 704 | |
| Flash point | −15 °C (5 °F; 258 K) |
| 49 °C (120 °F; 322 K) | |
| Explosive limits | 3.7–12.5% |
| Lethal dose or concentration (LD, LC): | |
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LD50 (median dose)
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25 mg/kg (rat, oral) |
| US health exposure limits (NIOSH): | |
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PEL (Permissible)
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none |
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REL (Recommended)
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TWA 0.1 ppm (0.23 mg/m3) ST 0.2 ppm (0.45 mg/m3) |
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IDLH (Immediate danger)
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N.D. |
| Related compounds | |
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Other cations
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Triruthenium dodecacarbonyl Triosmium dodecacarbonyl |
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Related iron carbonyls
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Diiron nonacarbonyl Triiron dodecacarbonyl |
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Related compounds
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Dimanganese decacarbonyl Dicobalt octacarbonyl Nickel tetracarbonyl |
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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 | |
Iron pentacarbonyl, also known as iron carbonyl, is the compound with formula Fe(CO)5. Under standard conditions Fe(CO)5 is a free-flowing, straw-colored liquid with a pungent odour. Older samples appear darker. This compound is a common precursor to diverse iron compounds, including many that are useful in small scale organic synthesis.
Iron pentacarbonyl is a homoleptic metal carbonyl, where carbon monoxide is the only ligand complexed with a metal. Other examples include octahedral Cr(CO)6 and tetrahedral Ni(CO)4. Most metal carbonyls have 18 valence electrons, and Fe(CO)5 fits this pattern with 8 valence electrons on Fe and five pairs of electrons provided by the CO ligands. Reflecting its symmetrical structure and charge neutrality, Fe(CO)5 is volatile; it is one of the most frequently encountered liquid metal complexes. Fe(CO)5 adopts a trigonal bipyramidal structure with the Fe atom surrounded by five CO ligands: three in equatorial positions and two axially bound. The Fe–C–O linkages are each linear.
Fe(CO)5 exhibits a relatively low rate of interchange between the axial and equatorial CO groups via the Berry mechanism.
Purified iron pentacarbonyl can be decomposed to produce carbonyl iron, a high-purity preparation of iron metal.