The study of relationship between chemical geometry and electronic configuration, non-Walsh type B Part II

In this research, we will introduce non-Walsh type B and extra five driving forces in molecular geometry determination, and demonstrate them in this paper. The question first came to our mind when we considered that CH3 radical has planar structure, but SiH3 radical is in bent form, while both molecules have an electron on central atom from Lewis structure viewpoint, and they must have bent structure according to Walsh rule. We will show three contrasts in current theory; there are many molecules which do not follow Lewis valence theory and Walsh rule, and also they have spin multiplicity, but they do not show torsion in molecule. Therefore, we are looking for some types of existing interactions between different molecular orbitals in particular type of category of molecules: AX3, AH2X and AHX2 in the form of radical, cation and anions, where A is C, Si, Ge, N or P atom, and X is F, Cl or Br atom. In spite of studying one category of compound in this article, a generalized method for investigation of these types of interactions will be presented, which can be used in other similar cases. We will demonstrate the reasons for such molecules having particular geometry, which are caused by some interactions such as lone pair of X-atom with radical electron on A-atom, lone pair of X and σ-bond, hybridization of electrons on central atom, back bonding and spin multipilicity. B3lyp with 6-311G** basis set have been applied to our calculations, and atom in molecule (AIM), natural bond orbital (NBO), are also used for the results analysis.