Chemistry - Coordination Chemistry Question with Solution | TestHub

The ${\mathrm{t}}_{2\mathrm{g}}$ (triplet, lower energy) orbitals are the ${\mathrm{d}}_{\mathrm{xy}}, {\mathrm{d}}_{\mathrm{xz}}$ and ${\mathrm{d}}_{\mathrm{yz}}$ orbitals. The ${\mathrm{e}}_{\mathrm{g}}$ (doublet, higher energy) orbitals are the ${\mathrm{d}}_{{\mathrm{z}}^2}$ and ${\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$ orbitals. These split d-orbitals are called ${\mathrm{t}}_{2\mathrm{g}}$ and ${\mathrm{e}}_{\mathrm{g}}$because they are split by the effect of the surrounding ligand ions in a crystal field.

${\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$ Contains ${\mathrm{Cr}}^{3+}:\left[\mathrm{Ar}\right]3{\mathrm{d}}^3:{\mathrm{t}}_{2\mathrm{g}}^3{\mathrm{e}}_{\mathrm{g}}^{\mathrm{o}}$
${\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$ Contains ${\mathrm{Fe}}^{3+}:\left[\mathrm{Ar}\right]3{\mathrm{d}}^5:{\mathrm{t}}_{2\mathrm{g}}^3{\mathrm{e}}_{\mathrm{g}}^2$
${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ Contains ${\mathrm{Ni}}^{2+}:\left[\mathrm{Ar}\right]3{\mathrm{d}}^8:{\mathrm{t}}_{2\mathrm{g}}^6{\mathrm{e}}_{\mathrm{g}}^2$

${\left[\mathrm{V}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$ Contains ${\mathrm{V}}^{3+}:\left[\mathrm{Ar}\right]3{\mathrm{d}}^2:{\mathrm{t}}_{2\mathrm{g}}^2{\mathrm{e}}_{\mathrm{g}}^{\mathrm{o}}$