Abstract In acid perchlorate media ([H+]= 1.0–3.0 M), each mole of paracetamol, HOC 6 H 4 NHCOCH 3 (APAP), at ambient temperature quantitatively reduces two mole of the metallo- superoxo complex, μ-superoxo-bis [pentaamminecobalt (III)] 5+,[(NH 3) 5 Co (III)(μ-O 2) Co (III)(NH 3) 5] 5+(1). Here, complex 1 is reduced to [(NH 3) 5 Co (OH 2)] 3+, Co 2+, O 2 and NH 4+ and APAP itself is oxidised to quinone oxime and acetic acid. With a large excess ...