Question

Which of following organometallic compound is $\sigma$ and $\pi$ bonded

• A. [Fe(η5 – C5H5)2]
• B. K[PtCl3(η2– C2H4)]
• C. [Co(CO)5NH3]+2
• D. Fe(CH3)3

Answer 1

Answer: (C)

[Co(CO)5NH3]+2

Answer 2

The correct option is(C): [Co(CO)5NH3]+2.

$\sigma$ Bonds: In this complex, the bond between the cobalt atom (Co) and the ammonia molecule (NH3) is a $\sigma$ (sigma) bond. Sigma bonds are formed by the head-on overlap of atomic orbitals.

$\pi$ Bonds: The five carbon monoxide (CO) ligands in the complex are bonded to the cobalt atom via $\pi$ (pi) bonds. Pi bonds result from the side-to-side overlap of p orbitals. Each CO ligand contributes one π bond to the complex, and since there are five CO ligands, there are a total of five $\pi$bonds.

So, [Co(CO)5NH3]+2 contains both $\sigma$ and $\pi$ bonds,