For the most stable oxidation state of manganese is 2, it has a pink to red, many of manganese (II) compounds are known , such as manganese(II) sulfate (MnSO4) and manganese(II) chloride (MnCl2). This oxidation state is also seen in the mineral rhodochrosite, (manganese(II) carbonate). The +2 oxidation state is the state used in living organisms for essential functions; other states are toxic for human body.