Find the number of paramagnetic and inner orbital complexes among the following:
[Ni(CO)₄], [Ni(CN)₄]²⁻, [Co(H₂O)₆]³⁺, [Mn(CN)₆]⁴⁻, [Cr(NH₃)₆]³⁺, [Fe(CN)₆]³⁻

Question

Find the number of paramagnetic and inner orbital complexes among the following: [Ni(CO)₄], [Ni(CN)₄]²⁻, [Co(H₂O)₆]³⁺, [Mn(CN)₆]⁴⁻, [Cr(NH₃)₆]³⁺, [Fe(CN)₆]³⁻

TestHub · Accepted Answer

Complex	Metal ion configuration	Magnetic nature	Inner orbital?
$[Ni (CO)_{4}]$	Ni⁰ : $3 d^{8} 4 s^{2} \to d^{10}$	Diamagnetic	No (tetrahedral)
$[Ni (CN)_{4}]^{2 -}$	Ni²⁺ : $d^{8}$	Diamagnetic	Yes ( $dsp^{2}$ )
$[Co (H_{2} O)_{6}]^{3 +}$	Co³⁺ : $d^{6}$	Diamagnetic	Yes ( $d^{2} sp^{3}$ )
$[Mn (CN)_{6}]^{4 -}$	Mn²⁺ : $d^{5}$	Paramagnetic	Yes ( $d^{2} sp^{3}$ )
$[Cr (N H_{3})_{6}]^{3 +}$	Cr³⁺ : $d^{3}$	Paramagnetic	Yes ( $d^{2} sp^{3}$ )
$[Fe (CN)_{6}]^{3 -}$	Fe³⁺ : $d^{5}$	Paramagnetic	Yes ( $d^{2} sp^{3}$ )

Paramagnetic complexes:

$[Mn (CN)_{6}]^{4 -}$ , $[Cr (N H_{3})_{6}]^{3 +}$ , $[Fe (CN)_{6}]^{3 -}$

$\Rightarrow$ 3

Inner orbital complexes:

$[Ni (CN)_{4}]^{2 -}$ , $[Co (H_{2} O)_{6}]^{3 +}$ , $[Mn (CN)_{6}]^{4 -}$ , $[Fe (CN)_{6}]^{3 -}$

$\Rightarrow$ 5

Therefore,

$P a r ama g n e t i cco m pl e x es = 3$ $I nn eror bi t a l co m pl e x es = 5$

number of complexes that are both paramagnetic and inner orbital, the answer is:

$3$

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