Which of the following carbonyls will have the strongest C-O bond

Options

A. `[Mn(CO)_6]^(+)`
B. `[Cr(CO)_6]`
C. `[V(CO)_6]^(-)`
D. `[Fe(CO)_5]`

Answer

A

Explanation

As positive charge on the central metal atom increases, the less readily the metal can donate electron density into the `pi^(**)` orbitals of CO result in weakening of C-O bond). Hence, the C-O bond would be strongest in `[Mn(CO)_6]^+`