Tetracobalt dodecacarbonyl

Tetracobalt dodecacarbonyl
Names
Other names
cobalt dodecacarbonyl, cobalt carbonyl
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.037.951 Edit this at Wikidata
EC Number
  • 241-763-1
  • InChI=1S/12CO.4Co/c12*1-2;;;;
    Key: YMFAWOSEDSLYSZ-UHFFFAOYSA-N
  • [Co-2]1235(C#[O+])(C#[O+])C(=O)[Co-2]246(C#[O+])(C#[O+])C(=O)[Co-2]34(C#[O+])(C#[O+])(C1=O)[Co-3]56(C#[O+])(C#[O+])C#[O+]
Properties
Co4(CO)12
Molar mass 571.858 g/mol
Appearance black crystal
Density 2.09 g/cm3
Melting point decomposes at 60 °C (140 °F; 333 K)
Hazards
GHS labelling:
GHS02: FlammableGHS08: Health hazardGHS09: Environmental hazard
Warning
H228, H301, H317, H331, H351
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Tetracobalt dodecacarbonyl is the chemical compound with the formula Co4(CO)12. It is a black crystalline compound that is insoluble in water and easily oxidized by air. It is an example of a metal carbonyl cluster.

Synthesis and structure

This compound is synthesized by decarbonylation of Co2(CO)8.

2 Co2(CO)8 → Co4(CO)12 + 4 CO

The molecule consists of a tetrahedral Co4 core, but the molecular symmetry is C3v. Three carbonyl ligands are bridging ligands and nine are terminal.[1] The average Co-Co distance is 2.499 Å, the average C-O bond length is 1.133 Å, and the average Co-C-O angle is 177.5°.[2][3]

Rh4(CO)12 adopts the same C3v structure but Ir4(CO)12 has perfect Td symmetry with no bridging CO ligands groups.[4] The Rh4 and Ir4 clusters are more thermally robust than that of the Co4 compound, reflecting the usual trend in the strengths of metal-metal bond for second and third row metals vs those for the first row metals. There has been disagreement between the theoretically predicted and experimental structure of tetracobalt dodecacarbonyl.[5][4][6]

References

  1. ^ Chini, P. (1968). "The closed metal carbonyl clusters". Inorganica Chimica Acta. 2: 31–51. doi:10.1016/0073-8085(68)80013-0.
  2. ^ Farrugia, L. J.; Braga, D.; Grepioni, F. (1999). "A structure redetermination of Co4(CO)12: evidence for dynamic disorder and the pathway of metal atom migration in the crystalline phase". Journal of Organometallic Chemistry. 573 (1–2): 60–66. doi:10.1016/S0022-328X(98)00879-1.
  3. ^ Corradini, P. (1959). "Structure of tetracobaltdodecarbonyl". Journal of Chemical Physics. 31 (6): 1676–1677. Bibcode:1959JChPh..31.1676C. doi:10.1063/1.1730674.
  4. ^ a b Wei, C. H. (1969). "Structural analyses of tetracobalt dodecacarbonyl and tetrarhodium dodecacarbonyl. Crystallographic treatments of a disordered structure and a twinned composite". Inorganic Chemistry. 8 (11): 2384–2397. doi:10.1021/ic50081a030.
  5. ^ Corradini, Paolo (1959). "Structure of tetracobaltdodecarbonyl". Journal of Chemical Physics. 31 (6): 1676–1677. Bibcode:1959JChPh..31.1676C. doi:10.1063/1.1730674.
  6. ^ Farrugia, Louis J.; Braga, Dario; Grepioni, Fabrizia (1999). "A structure redetermination of Co4(CO)12: Evidence for dynamic disorder and the pathway of metal atom migration in the crystalline phase". Journal of Organometallic Chemistry. 573 (1–2): 60–66. doi:10.1016/S0022-328X(98)00879-1.