In this study, laminar flame speeds at atmospheric pressure are accurately measured for H-2/Cl-2/N-2 mixtures at different equivalence ratios and N-2 mole fractions by the counterflow flame technique. A kinetic mechanism based on recently published and evaluated rate constants is developed to model these measured laminar flame speeds as well as the literature data on the concentrations of H-2, Cl-2, and HCl species in flat-burner flames and the ignition delay times from shock tube experiments. The kinetic model yields satisfactory comparison with these experimental data, and suggests that the reactions involving excited HCl(v) species and energy branching are not of substantial significance in combustion situations, and that the use of accurate elementary rate constants is instead crucial to the accuracy of the reaction mechanism. (c) 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved.