Question

In which compound synergic effect is present?

• A. $\left[Mn\right(H_{2}O{)}_6{]}^{2+}$
• B. $[CuC{l}_4{]}^{2-}$
• C. $\left[Ni\right(CO{)}_4]$
• D. $[NiC{l}_4{]}^{2-}$

Answer 1

The correct option is C $\left[Ni\right(CO{)}_4]$

The $M-C\pi$ bond in metal carbonyl which is formed by the donation of an electron pair from a filled d-orbital of metal into the vacant antibonding $\pi -$ orbital of $CO$, strengthen the $M-C\sigma -$ bond. This is called synergic effect and is usually observed in metal carbonyls. Thus, $\left[Ni\right(CO{)}_4]$ exhibit synergic bonding.