Chemistry - Coordination Chemistry Question with Solution | TestHub

${\mathrm{Mn}}^{3+}\Rightarrow [\mathrm{Ar}]3{\mathrm{d}}^4$ ${\mathrm{d}}^4$ configuration in ${\mathrm{t}}_{2\mathrm{g}}$ and ${\mathrm{eg}}_{\mathrm{g}}$ orbitals will always have unpaired electrons irrespective of SFL and WFL. ${\mathrm{Fe}}^{3+}\Rightarrow [\mathrm{Ar}]3{\mathrm{d}}^5$ ${\mathrm{d}}^5$ configuration will also have unpaired electron irrespective of SFL and WFL. ${\mathrm{Co}}^{3+}\Rightarrow [\mathrm{Ar}]3{\mathrm{d}}^6$ ${\mathrm{d}}^6\Rightarrow$ it can be both paramagnetic or diamagnetic based on field of ligands. In case of ${\mathrm{F}}^{-}\Rightarrow$ weak field ligand, configuration will be ${\mathrm{t}}_{2\mathrm{g}}^4{\mathrm{e}}_{\mathrm{g}}^2$ hence it is paramagnetic but in case of en $\Rightarrow$ strong filed ligand, configuration will be ${\mathrm{t}}_{2\mathrm{g}}^6{\mathrm{e}}_{\mathrm{g}}^0$ hence it will be diamagnetic. So, ${\left[\mathrm{Mn}\left({\mathrm{NH}}_3\right)6\right]}^{3+}$ : Paramagnetic ${\left[{\mathrm{MnCl}}_6\right]}^{3-}$ : Paramagnetic ${\left[{\mathrm{FeF}}_6\right]}^{3-}$ : Paramagnetic ${\left[{\mathrm{CoF}}_6\right]}^{3-}$ : Paramagnetic ${\left[\mathrm{Fe}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$ : Paramagnetic ${\left[\mathrm{Co}(\mathrm{en}{)}_3\right]}^{3+}$ : Diamagnetic Only 1 complex is diamagnetic.