Question

The formula of a carbonyl complex of a cobalt\[,{\left( {CO} \right)_n}Co - Co{\left( {CO} \right)_n},\], in which there is only a single Co-Co bond is:
A. \[C{o_2}{\left( {CO} \right)_4}\]
B. \[C{o_2}\left( {CO} \right)6\]
C. \[C{o_2}{\left( {CO} \right)_8}\]
D. \[C{o_2}{\left( {CO} \right)_{10}}\]

Answer 1

Hint:
The homoleptic carbonyls (compounds containing carbonyl ligands only) are formed by most of the transition metals. These carbonyls have simple, well defined structures. The oxidation number of cobalt is 0.

Complete Step By Step Solution:
The carbonyl complex of cobalt having a single Co-Co bond is \[C{o_2}{\left( {CO} \right)_8}\].

Metal Carbonyls have synergic bonding interactions. The metal carbon bond in metal carbonyl has both s and p characters. The Metal-Carbon bond formed by donation of lone pair from the carbonyl carbon into vacant orbital of metal.$\pi $ Bond between metal and carbon is formed by the donation of a pair of electrons from a filled d orbital of metal into the vacant anti bonding $\pi * $ orbital of carbon monoxide. This bonding makes the bond very strong.
Correct option is C.

Additional Information:
This dicobalt octacarbonyl is a reagent and catalyst in organometallic chemistry and organic synthesis. It is used as a catalyst for hydroformylation, the conversion of alkenes into aldehydes.

Note:
Go and see NCERT all details are given there. You have to remember the structure and also understand the concept of synergic bonding. As there is only one structure of cobalt compound in NCERT so you easily find and learn it.