\(\mathrm{MnO}_4^{-} \Rightarrow \mathrm{Mn}^{+7} \mathrm{e}^0 \mathrm{t}_2^0\)
\(\mathrm{FeO}_4^{2-} \Rightarrow \mathrm{Fe}^{+6} \mathrm{e}^2 \mathrm{t}_2^0\)
\(\mathrm{FeCl}_4^{2-} \Rightarrow \mathrm{Fe}^{+2} \mathrm{e}^3 \mathrm{t}_2^3\)
\(\mathrm{CoCl}_4^{2-} \Rightarrow \mathrm{Co}^{+2} \mathrm{e}^4 \mathrm{t}_2^3\)
(પ. ક્ર.: $Sc = 21 , Ti = 22, V = 23, Zn = 30$)