Interaction of carbonyiferrate anions Fen(CO)I~,T_4 and hydridocarbonylferrate anions HFen(CO)~. q (where n = I--4; m = 5, 9, 12, 14, respectively) with Bronstad and Lewis acids HX (X = AcO, CF3CO 2, HSO4) and RX(R = Alk, Ac, Bn, Bz; X = CI, Br) isa radical-chain process, oecuring via a one-electron redox-initiation stage, including preliminary activating complex formation. A common approach to the description of the processes of reduction and carbonylation of different organic compounds was suggested. It is based upon the exchange reactions and the interconversions within the coordination spheres of 17-electron coordinatively unsaturated iron earbonyl radical anions. Fe,(CO)",~T--I-