Question

What is the number of unpaired electrons of nickel observed in \[\ce{[Ni(CN)4]^{2-}}\]?

Options

• 6

• Zero

• 2

• 4

Answer 1

Zero

Explanation:

In the complex \[\ce{[Ni(CN)4]^{2-}}\] Ni is in + 2 oxidation state. Hence, electronic configuration of Ni²⁺ is

\[\ce{Ni^{2+} = [Ar] 3d^8}\]

It is dsp² hybridised using 4 - dsp² hybrid orbitals, each of which has 8 electrons from 4 cyanide ligands. 3d-orbitals contain the 8 electrons that makeup Ni. Thus, all electrons are paired. Hence, it contains zero unpaired electrons.