COMEDK2025ChemistryCoordination CompoundsActual
The 'd' electronic configuration of [ Ru ( en )₃ ] Cl ₂ and [ Fe ( H ₂ O )₆ ] Cl ₂ respectively are _____ and ____ . [Given: Atomic number of Ru =44 and Fe =26 ]
Options
- At_ 2 g ^6 e_g^0 ; t_ 2 g ^6 e_g^0
- Bt_ 2 g ^6 e_g^0 ; t_ 2 g ^4 e_g^2
- Ct_ 2 g ^4 e_g^2 ; t_ 2 g ^6 e_g^0
- Dt_ 2 g ^4 e_g^2 ; t_ 2 g ^4 e_g^2
Correct answer
B. t_ 2 g ^6 e_g^0 ; t_ 2 g ^4 e_g^2
Step-by-step solution
For [ Ru ( en )₃ ] Cl ₂ , the oxidation state of Ru is +2 . The atomic number of Ru is 44 , so its electronic configuration is [ Kr ] 4d^7 5s^1 . For Ru ²⁺ , the configuration is 4d^6 . Since Ru is a 4d transition metal, it forms low-spin complexes regardless of the ligand field strength. Thus, the d^6 configuration in an octahedral field results in t_ 2g ^6 e_g^0 . For [ Fe ( H ₂ O )₆ ] Cl ₂ , the oxidation state of Fe is +2 . The atomic number of Fe is 26 , so its electronic configuration is [ Ar ] 3d^6 4s^2 . Fo