Question

Which of the following compounds is square planar and does not have any unpaired electron?

• A. $Ni ( CO )_{4}$
• B. $\left[ Ni \left( H _{2} O \right)_{6}\right]^{2+}$
• C. $\left[ NiCl _{4}\right]^{2-}$
• D. $\left.\left[ Ni ( CN )_{4}\right)\right]^{2-}$

Answer 1

Answer: (D)

In $\left[ Ni ( CN )_{4}\right]^{2-},$ oxidation state of $Ni =+2$

$Ni ^{2+} \rightarrow 3 d^{8}$



$d s p^{2}$ hybridisation results in square planar geometry, with no unpaired electrons.