Which of the following ions exhibits d-d transitions and paramagnetism as well?

Options

A. `CrO_(4)^(2-)`
B. `Cr_(2)O_(7)^(2-)`
C. `MnO_(4)^(-)`
D. `MnO_(4)^(2-)`

Answer

D

Explanation

The no. of unpaired electrons in all the ions are listed.
In `CrO_(4)^(2-),Cr^(+6)(n=0)` diamagnetic
In `Cr_(2)O_(7)^(2-),Cr^(+6)(n=0)` diamagnetic
In `MnO_(4)^(-),Mn^(+7)(n=0)` diamagnetic
In `MnO_(4)^(2-),Mn^(+6)(n=1)` diamagnetic
Thus `MnO_(4)^(2-)` ion is paramagnetic and also exhibits d-d transition.