Ab Initio Predictions for Thermochemical Parameters for Tin−Oxygen Compounds

Heats of formation have been determined for the tin−oxygen compounds SnO, SnO 2, H 2 SnO, and H 3 SnOH by ab initio computations of reaction energies for isogyric reactions. The electronic structure methods employed include the coupled-cluster singles and doubles method with a perturbative correction for connected triple substitutions [CCSD(T)] and the Brueckner doubles method with analogous corrections for triple and quadruple substitutions [BD(TQ)]. Correlation-consistent triple- and quadruple-ζ basis sets were employed in conjunction with a large-core pseudopotential and a core polarization potential for Sn, and a basis set incompleteness correction was computed from extrapolations to the infinite basis set limit. Values of 9 ± 4, 10 ± 4, 34 ± 4, and −20 ± 4 kcal mol -1 are proposed for for SnO, SnO 2, H 2 SnO, and H 3 SnOH, respectively. Polynomial fits were carried out for the heat capacity and the standard enthalpy and entropy over the 300−3100 K temperature range.