A self-consistent set of thermochemical parameters for 39 molecules in the Si-H-O-Cl system have been calculated using the BAC-MP4 method. The BAC-MP4 method combines ab initio electronic structure calculations with empirical corrections to obtain accurate heats of formation. Both stable and radical species are included in the study, as well as several complexes formed by reaction with gas-phase water. Although there are almost no experimental data available for comparison, trends within homologous series and calculated bond dissociation energies are consistent with previous BAC-MP4 predictions for silicon compounds. Polynomial fits of the predicted thermodynamic data over the 300-3000 K temperature range are included in the Supporting Information. The thermodynamic data are used to evaluate the energetics of reactions that may be involved in the oxidation and hydrolysis of silicon tetrachloride, in particular the reactions of SiCl3 and SiCl2 with O-2 and H2O.