In the Iso-electronic series of metal carbonyls, the C-O bond strength is expected to increase in the order:-

Options

A. `[Mn(CO)_(6)]^(+) lt [Cr(CN)_(6)] lt [V(CO)_(6)]^(-)`
B. `[V(CO)_(6)]^(-) lt [Cr(CO)_(6)] lt [Mn(CO)_(6)]^(+)`
C. `[V(CO)_(6)]^(-) lt [Mn(CO)_(6)]^(+) lt [Cr(CO)_(6)]`
D. `[Cr(CO)_(6)] lt [Mn(CO)_(6)]^(+) lt [V(CO)_(6)]^(-)`

Answer

D

Explanation

CO bond strength is reciprocal to the extent of back donation involved in synergic bonding i.e., `M hArr CO`