Question

Select the correct statement among the following.

• A. Co (III) is stabilised in presence of weak field ligands, while Co (II) is stabilised in presence of strong field ligand.
• B. Four coordinated complexes of Pd (II) and Pt (II) are paramagnetic and square planar.
• C. [Ni(CN)₄]^4- ion and [Ni(CO)₄] are tetrahedral and square planar respectively.
• D. Ni²⁺ ion does not form inner orbital octahedral complexes in presence of weak ligand fields.

Answer 1

Answer: (D)

This problem includes conceptual mixing of CFSE, CFT and magnetism in coordination compounds. This problem can be solved by usual understanding of each statement as explained below :

(I) Both Co²⁺ and Co³⁺ are stabilised in presence of strong of field ligands due to high CFSE values.

(II) Due to higher Zeft values on the valence shell Pd²⁺ and Pt²⁺ cations, they always form inner orbital complexes but are diamagnetic in nature and square planar.

(III) [Ni(CO)₄]; sp³, tetrahedral, $\mu =\text{0 BM}$

[Ni(CN)₄]^4- ; dsp², square planar, $\mu =\text{0 BM}$

(IV) In ${\text{Ni}}^{+2},$ pairing of electron do not occur in presence of weak field ligands, so they form an outer orbital complex.



Electronic distribution unaffected.