Hydroxyl radicals are able to form solute radical cations in acidic aqueous solutions of 1-bromo-n-chloroalkanes (n = 1-6). Depending on the value of n, the bromine centered radical cation stabilizes on coordination with an unoxidized bromine atom from another molecule (intermolecular) or with an unoxidized chlorine atom of the same molecule (intramolecular). With n = 2, 5, and 6, only dimer radical cations (lambda(max) 430-450 nm) are formed through intermolecular coordination, whereas, with n = 1, 3, and 4, radical cations are stabilized both by intra- and intermolecular coordination, forming intramolecular radical cations (lambda(max) = 380 nm) or dimer radical cations (lambda(max) = 425-440 nm) at low and high solute concentrations, respectively. Cl-2(.-) is unable to undergo an electron transfer reaction with 1-bromo-2-chloroethane whereas SO4.- is able to react with 1-bromo-2-chloroethane with a bimolecular rate constant of 8.3 x 10(6) dm(3) mol(-1) s(-1). The dimer radical cation of 1-bromo-2-chloroethane is a strong one-electron oxidant and is able to undergo electron transfer reactions with a number of molecules with high rate constant values (10(9) dm(3) mol(-1) s(-1)). The dimer radical cation decays by a deprotonation mechanism, and the stability constant is determined to be 147 dm(3) mol(-1) at 25 degrees C. Quantum chemical calculations of the strength of the three-electron bond between two heteroatoms at a semiempirical level with AM1 parametrization show good correlation with experimental results. Good correlation, between experimental results and theoretical calculations, is also observed for variation of the net atomic charge over bromine, the ionization potential (IP) of the molecule, and the difficulty of oxidation of various alkyl halides.