Q.

The complex with highest magnitude of crystal field splitting energy (Δ0) is              [2023]
 

1 [Cr(H2O)6]3+  
2 [Fe(H2O)6]3+  
3 [Ti(H2O)6]3+  
4 [Mn(H2O)6]3+  

Ans.

(1)

For octahedral complexes

CFSE=-0.4 nt2g+0.6 neg

For [Mn(H2O)6]3+: Mn3+⇒3d4 ⇒t2g1,1,1eg1,0 ⇒CFSE=-0.6 Δ0

For [Cr(H2O)6]3+: Cr3+⇒3d3 ⇒t2g1,1,1eg0,0 ⇒CFSE=-1.2 Δ0

For [Fe(H2O)6]3+: Fe3+⇒3d5 ⇒t2g1,1,1eg1,1 ⇒CFSE=0

For [Ti(H2O)6]3+: Ti3+⇒3d1 ⇒t2g1,0,0eg0,0 ⇒CFSE=-0.4 Δ0

∴ Complex [Cr(H2O)6]3+ has the highest value of CFSE.