do one of the paired electrons from t_2g level of octahedral field also gets exited to e_g level?

Dear Student

t_2g orbitals hold lower energy as compared to e_g orbital for octahedral complexes, therefore if there is only one paired electrons, then one will excite from t_2g level to e_g level depending on the value of $∆$_o in the complex. If ​$∆$_o 0s larger, there electrons would remain in the level with lower energy, i.e., t_2g , to give low-spin complexes also known as strong-field ligands, whereas in case the value of ​$∆$_o is smaller, then weak-field ligands are formed.

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