Manganates are dark green in colour with a visible absorption maximum of λ max 606 nm ε 1710 dm 3 mol 1 cm 1. As in the case of titanium vanadium and chromium the highest oxidation state 7 of manganese corresponds to the total number of 3 d and 4 s electrons. The 2 oxidation state is the state used in living organisms for essential functions.
