Key Idea: The magnitude of Δ∝ct (the orbital splitting energy) is decided by the nature of ligand Strong field ligand has highest Δoct . The increasing field strength is as I−<Br−<Cl−<F−<OH−<H2O<C2O42−<NH3<en<NO2−<CN− The CN−is the strongest ligand among these, hence the magnitude of Δoct will be maximum in [Co(CN)6]3−. Note : The magnitude of Δoct is also decided by oxidation state of the metal ion. Thus, greater the ionic charge on the central metal ion, the greater the value of Δoct . But here the oxidatinon state of Co metal ion is same in all complexes.
In which of the following coordination entities the magnitude of Δ_o (CFSE in octahedral field) will be maximum? (Atomic number Co=27 )
NEET UG 2008 — Chemistry Inorganic Chemistry
2008mcqmedium
In which of the following coordination entities the magnitude of Δo (CFSE in octahedral field) will be maximum? (Atomic number Co=27 )
Official previous-year question
Held on 30 Apr 2008 · Verified 9 Jul 2026.
Options
- A
[Co(H2O)6]3+
- B
[Co(NH3)6]3+
- C
[Co(CN)6]3−
- D
[Co(C2O4)3]3−
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