Question

Compare crystal field splitting energy(Δ) for given complexes 

(i) K₄[Fe(CN)₆] 

 (ii)  [Cu(NH₃)₄ ]⁺² s 

(iii) K₄ [Fe(SCN)₆] 

(iv) [Fe(en)₃ ]Cl₃ 

(1) I > II > III > IV 

(2) II > I > IV > III 

(3) IV > I > III > II 

(4) IV > III > I > II

Answer 1

Correct option is: (2) II > I > IV > III 

\(K_4 [Fe(CN)_6] \Rightarrow d^6 \Rightarrow SFL,\)

\(K_2 [Cu(NH_3)_4] \Rightarrow d^9 \Rightarrow dsp^2\)

\(K_4 [Fe(SCN)_6] \Rightarrow d^6 \Rightarrow WFL\)

\([Fe(en)_3]Cl_3 \Rightarrow d^5 \Rightarrow SFL\)

Splitting energy \(\propto\) Strength of ligand \(\propto\) Charge of CA

\(\Delta _{sp} > \Delta _o\)

II > I > IV > III