Question

What should be possible $d$-orbital energy levels of $Ni$ in $[Ni(CN)_4]^{2-}$ ?

• A. $d_{z^{2}} < d_{xy} < d_{xy} = d_{yz} < d_{x^{2}-y^{2}}$
• B. $d_{x^{2}-y^{2}} < d_{xy} < d_{z^{2}} < d_{xy} = d_{yz}$
• C. $d_{xy} = d_{yz} < d_{z^{2}} < d_{xy} < d_{x^{2}-y^{2}}$
• D. $d_{z^{2}} < d_{xy} = d_{yz} < d_{xy} < d_{x^{2}-y^{2}}$

Answer 1

Answer: (C)

$d_{xy} = d_{yz} < d_{z^{2}} < d_{xy} < d_{x^{2}-y^{2}}$

Answer 2

$[Ni(CN)_{4}]^{2-}$ has square planar geometry with $dsp^{2}$ hybridisation
The order of energies of $d$-orbitals in square planar geometry is:
$d_{xy}=d_{yz} < d_{z^{2}} < d_{xy} < d_{x^{2} -y^{2}}$