Smog chamber/FTIR techniques were used to study the kinetics and mechanism of the reaction of Cl atoms with iodobenzene (C6H5I) in 20-700 Torr of N-2, air, or O-2 diluent at 296 K. The reaction proceeds with a rate constant k(Cl + QH(5)I) = (3.3 +/- 0.7) x 10(-11) cm(3) molecule(-1) s(-1) to give chlorobenzene (C6H5Cl) in a yield which is indistinguishable from 100 The title reaction proceeds via a displacement mechanism (probably addition followed by elimination). (C) 2001 Elsevier Science B.V. All rights reserved.