Question

In which of the following compounds transition metal is in oxidation state zero

• A. $\left[Co{\left({NH}_3\right)}_6\right]{Cl}_2$
• B. $\left[Fe{\left(H_{2}O\right)}_6{SO}_4\right]$
• C. $\left[Ni\right(CO{)}_4]$
• D. $\left[Fe{\left(H_{2}O\right)}_3\right](OH{)}_2$

Answer 1

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

Nickel shows zero oxidation state in carbonyl complex as $CO$ ligand has $0$ charge and complex as a whole also has $0$ charge. So, central metal atom has $0$ charge.