Consider [NiCl4]^2- (tetrahedral), [Ni(CN)4]^2- (square planar), [Ni(NH3)6]^2+ (octahedral) and Ni(CO)4. Which two have the same NON-ZERO spin-only magnetic moment?

JEE Advanced levelSingle correct optionDifficulty 3 of 3cc201

Consider $[NiCl X_{4}] X^{2 -}$ (tetrahedral), $[Ni (CN) X_{4}] X^{2 -}$ (square planar), $[Ni (NH X_{3}) X_{6}] X^{2 +}$ (octahedral) and $Ni (CO) X_{4}$ . Which two have the same NON-ZERO spin-only magnetic moment?

[NiCl X_{4}] X^{2 -}

d^{8}

with

n = 2

(

2.83

BM).

[Ni (NH X_{3}) X_{6}] X^{2 +}

t_{2 g}^{6} e_{g}^{2}

with

n = 2

(

2.83

BM).

[Ni (CN) X_{4}] X^{2 -}

and

Ni (CO) X_{4}

are diamagnetic (zero). Hence the pair is

[NiCl X_{4}] X^{2 -}

and

[Ni (NH X_{3}) X_{6}] X^{2 +}