Question

In which one of the following metal carbonyls, CO forms a bridge between metal atoms?

• A. \(\text{[Co}_2(\text{CO})_8]\)
• B. \(\text{[Mn}_2(\text{CO})_{10}]\)
• C. \(\text{[Os}_3(\text{CO})_{12}]\)
• D. \(\text{[Ru}_3(\text{CO})_{12}]\)

Answer 1

The Correct Option is A

To determine in which of the given metal carbonyls the carbon monoxide (CO) forms a bridge between metal atoms, we need to examine the structures of these complex metal carbonyls. 

1. \(\text{[Co}_2(\text{CO})_8]\): This metal carbonyl contains cobalt atoms bridged by CO ligands. In its structure, some of the CO molecules act as bridging ligands, forming a bond between two cobalt atoms.
2. \(\text{[Mn}_2(\text{CO})_{10}]\): This complex consists of two manganese atoms but does not exhibit CO as bridging ligands. All COs are terminal.
3. \(\text{[Os}_3(\text{CO})_{12}]\): In this complex, osmium atoms are involved, but the CO ligands are typically terminal, not forming bridges.
4. \(\text{[Ru}_3(\text{CO})_{12}]\): Similarly, in this ruthenium complex, the CO ligands serve as terminal ligands, not bridging the metal atoms.

Explanation: In \(\text{[Co}_2(\text{CO})_8]\), the presence of bridging CO ligands is a unique feature that distinguishes it from the other metal carbonyls listed. The complex forms a tetrahedral structure where CO can serve as bridging ligands between the two metal centers.

Therefore, the correct answer is \(\text{[Co}_2(\text{CO})_8]\), where CO forms a bridge between metal atoms.