For a set of 7 selected stable intermediates and derived radicals for the formation of 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins front 2,4,6-trichlorophenol, energy minimum structures, total atomic spin densities p, harmonic vibrational wavenumbers v ($) over bar, principal moments of inertia I-A, I-B, and I-C. heat capacities C-P(0)(T), entropies S-0(T), enthalpy increments H-0(T) - H-0(0), and standard enthalpies of formation Delta H-f(0)(T) were calculated at the G3MP2B3 level of theory and presented for T = 298.15 K. A set of 7 reaction paths is characterized by means of enthalpies of reaction Delta H-r(0)(298.15). (c) 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved.