Sodium tetracarbonylcobaltate

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.^[1] According to X-ray crystallography, the Co(CO)₄^- center is nearly tetrahedral (isoelectronic with Ni(CO)₄).^[2]

Sodium tetracarbonylcobaltate

Identifiers
CAS Number	14878-28-5 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.225.207
InChI InChI=1S/4CO.Co.Na/c4*1-2;;/q;;;;-1;+1 Key: REACDJLEGGOITP-UHFFFAOYSA-N
SMILES [Co-](C#O)(C#O)(C#O)C#O.[Na+]
Properties
Chemical formula	C4CoNaO4
Molar mass	193.963 g·mol−1
Appearance	white solid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Conventionally, this compound is prepared by reduction of dicobalt octacarbonyl with sodium amalgam]]:^[1]

Co₂(CO)₈ + 2 Na → 2 NaCo(CO)₄

It reacts with mercuric cyanide to give a HgCo2 derivative:^[3]

Hg(CN)₂ + 2 NaCo(CO)₄ → Hg[Co(CO)₄]₂ + 2 NaCN