sodium tetracarbonylcobaltate

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| ImageFile = NaCo(CO)4.svg

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| CASNo = 14878-28-5

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| InChI=1S/4CO.Co.Na/c4*1-2;;/q;;;;-1;+1

| InChIKey=REACDJLEGGOITP-UHFFFAOYSA-N

| SMILES = [Co-](C#O)(C#O)(C#O)C#O.[Na+]

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|Section2={{Chembox Properties

| Na = 1|Co=1|C=4|O=4

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| Appearance = white solid

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Sodium tetracarbonylcobaltate is the organocobalt compound with the formula NaCo(CO)₄. It is a common derivative of the tetracarbonylcobaltate anion, [Co(CO)₄]^-, although several other alkali metal salts are known. The tetracarbonylcobaltate anion is the conjugate base of cobalt tetracarbonyl hydride, HCo(CO)₄.{{cite book |doi=10.1002/047084289X.rs105 |chapter=Sodium Tetracarbonylcobaltate |title=Encyclopedia of Reagents for Organic Synthesis |date=2001 |last1=Kerr |first1=William J. |isbn=0-471-93623-5 }} According to X-ray crystallography, the Co(CO)₄^- center is nearly tetrahedral (isoelectronic with Ni(CO)₄).{{cite journal |doi=10.1524/zkri.1984.167.3-4.275 |title=Die Kristallstrukturen von LiCo(CO)₄und NaCo(CO)₄ |date=1984 |last1=Klüfers |first1=Peter |journal=Zeitschrift für Kristallographie |volume=167 |issue=3–4 |pages=275–286 |bibcode=1984ZK....167..275K }}

Conventionally, this compound is prepared by reduction of dicobalt octacarbonyl with sodium amalgam]]:

:{{chem2|Co2(CO)8 + 2 Na -> 2 NaCo(CO)4}}

It reacts with mercuric cyanide to give a HgCo2 derivative:{{cite journal |doi=10.1039/J19680001005 |title=The Crystal and Molecular Structure of Bis(tetracarbonylcobalt)mercury, Hg[Co(CO)4]2 |date=1968 |last1=Sheldrick |first1=G. M. |last2=Simpson |first2=R. N. F. |journal=Journal of the Chemical Society A: Inorganic, Physical, Theoretical |page=1005 }}

:{{chem2|Hg(CN)2 + 2 NaCo(CO)4 -> Hg[Co(CO)4]2 + 2 NaCN}}