Critical point properties of electron density distributions for oxide molecules containing first and second row cations

Abstract

Minimum energy geometries and electron density distributions, ϱ(r), for ∼40 polyatomic oxide molecules containing first and second row M-cations have been calculated at the Hartree-Fock level with a 6-311++G** basis set. The nature of the bonded interactions in these molecules is examined in terms of the relative electronegativities, χ M , of the M-cations and the properties of the electron density distribution, ϱ(r c ), evaluated at the bond critical points, r c , along each MO bond. As ϱ(r c ) and the Laplacian of ϱ(r c ) increase, χ M increases indicating an increase in the covalent character of the bonded interactions between M and O. The ratios of the curvatures of ϱ(r c ) indicate that the NO bond is predominantly covalent, that the CO and SO bonds are of intermediate type and that the remaining MO bonds are indicated to be predominantly ionic in character. A comparison of the critical point properties of ϱ(r c ) and χ M indicates that the minimum energy MO bond length is an important determinate of the properties of ϱ(r c ) and the character of the MO bonds.