Directed Covalent Bond in Group 16 Dihydrides

Abstract

The chemical bond lengths and angles of group 16 dihydrides were investigated. The relativistic effects are essential for heavy elements molecules calculations. Here we implement two relativistic effects, that is, scalar relativistic effects and spin-orbit coupled zero-order regular approximation. Concerning molecular symmetry, scalar relativistic effects and spin-orbit relativistic effects show different descriptions. They are single group and double group, respectively. In addition, non-relativistic effects were used for very weak relativistic effects on molecules and for comparing with and without relativistic effects for heavy element molecules. From H₂O to PoH₂, the bonding lengths and angles are due to sp hybridization orbitals, while LvH${\hspace{0.17em}}_2$ is mainly due to p-orbital bonding, resulting in a different configuration of bond lengths and angles than other group 16 dihydrides. The chemical bonding of group 16 dihydrides was analyzed from a single group point of view by operating the double group results to a single group.