JEE MainChemistryCoordination Compounds
A d^5 transition metal ion is placed in two different coordination environments: an octahedral field where the crystal field splitting energy is greater than the pairing energy ( _o > P ), and a tetrahedral field. The correct electronic configurations for the metal ion in the octahedral and tetrahedral fields, respectively, are :
Options
- At_ 2g ^3 e_g^2 and e^2 t₂^3
- Bt_ 2g ^5 e_g^0 and e^4 t₂^1
- Ct_ 2g ^5 e_g^0 and e^2 t₂^3
- Dt_ 2g ^3 e_g^2 and e^4 t₂^1
Correct answer
C. t_ 2g ^5 e_g^0 and e^2 t₂^3
Step-by-step solution
For an octahedral complex, if _o > P , the splitting energy is greater than the pairing energy. Electrons will pair up in the lower energy t_ 2g orbitals before occupying the e_g orbitals. For a d^5 ion, this results in a low spin configuration of t_ 2g ^5 e_g^0 . For a tetrahedral complex, the crystal field splitting energy _t is generally less than the pairing energy P (since _t = 4 9 _o ). Therefore, electrons will occupy the higher energy t₂ orbitals before pairing in the e orbitals. For a d^5 ion, this leads t