Select the high spin complexes from the following:
(A) $[Ni(CN)_4]^{2-}$
(B) $[Fe(CN)_6]^{3-}$
(C) $[MnBr_4]^{2-}$
(D) $[Fe(H_2O)_6]^{2+}$
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (C) and (D) only
High-spin complexes are formed when weak field ligands cause less pairing of electrons.
Let us check each complex:
- (A) [Ni(CN)₄]²⁻ → CN⁻ is a strong field ligand, square planar, low spin
- (B) [Fe(CN)₆]³⁻ → CN⁻ strong field, low spin
- (C) [MnBr₄]²⁻ → Br⁻ is a weak field ligand, tetrahedral, high spin
- (D) [Fe(H₂O)₆]²⁺ → H₂O is a weak field ligand, octahedral, high spin