Thermochemistry of hydrochlorofluoromethanes revisited: a theoretical study with the Gaussian-3 (G3) procedure

The heats of formation (Delta(f)H), ionization energies (IEs), proton affinities (PAs) and acidities of hydrochlorofluoromethanes (HCFMs) are calculated using the newly developed Gaussian-3 (G3) procedure, using MP2/6-31G(d) geometries and zero-point energies. Good overall agreement between G3 and experimental values are observed except major discrepancies found for five experimental values: the PAs of CH2F2, CHF3 and CF3Cl as well as the acidities of CH2F2 and CHF2Cl. Ignoring these five values, the agreement between the G3 results and the experimental data tin terms of mean-absolute-deviation) are within 4 kJ mol(-1) for Delta(f)H, 0.11 eV (11 kJ mol(-1)) for Ifs, 1 kJ mol(-1) for PAs and 8 kJ mol(-1) for acidities. (C) 1999 Elsevier Science B.V. All rights reserved.