Question

Which of the following complex has both s and p metal carbon bond?

• A. Bis(benzene)chromium
• B. Grignard reagent
• C. Iron(iii) hexacyanoferrate(ii)
• D. Iron pentacarbonyl

Answer 1

The correct option is D Iron pentacarbonyl

The metal-carbon bond in metal carbonyls possess both s and p character. The MC bond is formed by the donation of a lone pair of electrons on the carbonyl carbon into a vacant orbital of the metal. The MC bond is formed by the donation of a pair of electrons from a filled d orbital of metal into the vacant antibonding orbital of carbon monoxide. The metal to ligand bonding creates a synergic effect which strengthens the bond between CO and the metal.

Hence, answer is option D.