$$\mathrm{MnO}_{2}$$ तथा $$\mathrm{CrO}_{2} \mathrm{Cl}_{2}$$

$$\left[\mathrm{NiCl}_{4}\right]^{2-}$$ तथा $$\left[\mathrm{CoCl}_{4}\right]^{2-}$$

$$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$$ तथा $$\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]^{2-}$$

$$\left[\mathrm{FeCl}_{4}\right]^{-}$$ तथा $$\mathrm{Co}_{2} \mathrm{O}_{3}$$