Chemistry:Tetracobalt dodecacarbonyl
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| Other names
cobalt dodecacarbonyl, cobalt carbonyl
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3D model (JSmol)
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| 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 | |
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| GHS Signal word | 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). | |
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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
- ↑ Chini, P. (1968). "The closed metal carbonyl clusters". Inorganica Chimica Acta 2: 31–51. doi:10.1016/0073-8085(68)80013-0.
- ↑ 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.
- ↑ Corradini, P. (1959). "Structure of tetracobaltdodecarbonyl". Journal of Chemical Physics 31 (6): 1676–1677. doi:10.1063/1.1730674. Bibcode: 1959JChPh..31.1676C.
- ↑ 4.0 4.1 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.
- ↑ Corradini, Paolo (1959). "Structure of tetracobaltdodecarbonyl". Journal of Chemical Physics 31 (6): 1676–1677. doi:10.1063/1.1730674. Bibcode: 1959JChPh..31.1676C.
- ↑ 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.
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