D And F Block Elements

$\mathrm{Lu}^{3+}, \mathrm{Yb}^{2+}$

$\mathrm{Eu}^{3+}, \mathrm{Pm}^{2+}$

$\mathrm{Eu}^{2+}, \mathrm{Gd}^{3+}$

$\mathrm{La}^{3+}, \mathrm{Ce}^{4+}$