+5

+4

+6

+3

+6

+7

+8

+9

$\mathrm{Ti}^{3+}, \mathrm{V}^{2+}, \mathrm{Cr}^{3+}$ and $\mathrm{Mn}^{4+}$

$\mathrm{Ti}^{+}, \mathrm{V}^{4+}, \mathrm{Cr}^{6+}$ and $\mathrm{Mn}^{7+}$

$\mathrm{Ti}^{4+}, \mathrm{V}^{3+}, \mathrm{Cr}^{2+}$ and $\mathrm{Mn}^{3+}$

$\mathrm{Ti}^{2+}, \mathrm{V}^{3+}, \mathrm{Cr}^{4+}$ and $\mathrm{Mn}^{5+}$

Small atom like $\mathrm{C}, \mathrm{H}$ or N are trapped inside crystal lattice

They are usually non-stoichiometric

They generally retain metallic conductivity

They are chemically very active