Total number of unpaired electrons in the complex ion $[\ce{Co(NH3)6}]^{3+}$ and $[\ce{NiCl4}]^{2-}$ is

JEE Main · 2024 · 08 Apr 2024 · Shift 2 · Coordination Compounds

Total number of unpaired electrons in the complex ion

[Co (NH X_{3}) X_{6}]^{3 +}

and

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

Answer: 2

Solution

[C o (N H_{3})_{6}]^{3 +}

C o^{3 +}

d^{6}

;

N H_{3}

is a strong-field ligand giving low-spin octahedral

t_{2 g}^{6} e_{g}^{0}

— 0 unpaired electrons.

[N i C l_{4}]^{2 -}

N i^{2 +}

d^{8}

; tetrahedral geometry with weak-field

C l^{-}

gives

e^{4} t_{2}^{4}

— 2 unpaired electrons.
Total unpaired electrons

= 0 + 2 = 2

JEE Main · 2024 · 08 Apr 2024 · Shift 2 · Integer answer

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