The redox couples M/M+ of the Group I alkali metals Lithium, Sodium, Potassium, Rubidium and Caesium have been extensively investigated in a room temperature ionic liquid (IL) and compared for the first time. Cyclic voltammetric experiments in the IL N-butyl-N- methylpyrrolidinium bis (trifluoromethylsulfonyl) imide ([C4mpyrr][NTf2]) and subsequent simulation of the data has allowed the determination of the formal potential (Ef0 vs. ...