On the covalence in H2AuX (XÂ =Â F-I)

Theoretical investigations on the H2AuX (X = F-I) series have been performed at the CCSD(T) theoretical level with extended basis sets and the T-shaped stable structures were found. Mechanisms of Au-X and Au⋯H2 interactions were explored by NBO analysis, natural resonance theory, electron density deformation analyses, delocalization index and visualized by reduced density gradient analyses. Periodic trends are found in the bond length, stability and covalent nature of the Au-X interactions. For Au⋯H2 interactions, the delocalization index values and the electron density difference analysis show the “charge-shift covalent” type of interaction.