Carbonate radical shows moderate reactivity (k2=1.8·106 M-1 s-1) with nickelglycine complex. As an oxidizing free radical, it may attack the ligand to form Ni(II) coordinated glycine radical or oxidize the metal center to form a Ni(III) glycine transient. Continuous γ-irradiation of the complex-bicarbonate mixture yields glyoxalic acid (G=1.7) as the major product. The reaction involves an attack of the ligand and precludes the oxidation of metal center. © 1988 Akadémiai Kiadó.