Question

In $\mathrm{Ni}{\left(\mathrm{CO}\right)}_4$ what is the oxidation number of $\mathrm{Ni}$?

Answer 1

Step 1: Find the oxidation number

• The oxidation number is also known as the oxidation state, is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.
• $\mathrm{CO}$ is a neutral ligand, its oxidation state in metal carbonyl is 0.
• The total charge of $\mathrm{Ni}{\left(\mathrm{CO}\right)}_4$ is zero.
• The oxidation number of $\mathrm{Ni}$ be $x$.
• Therefore,

$$\begin{gathered} x+4\times \left(0\right)=0 \\ x-0=0 \\ x=0 \end{gathered}$$

• Hence, the oxidation number of $\mathrm{Ni}$ is $0$.