Question

For which of the following types of $d^n$ configuration, the number of unpaired electrons in octahedral complexes remains same irrespective of the ligand field strength.

• A. $d^3$
• B. $d^4$
• C. $d^5$
• D. $d^6$

Answer 1

The correct option is A $d^3$

For $d^3$ configuration, the number of unpaired electrons in octahedral complexes remains same irrespective of the ligand field strength.
Three electrons are present in $t_{2g}$ level and are unpaired. When the fourth electron enters, the ligand field strength will determine whether it will pair up or not.