A topographical study of bonding in the PP and SiP hydrides

Hydrogen-bridged structures are well known in H4Si2 and H2Si2 systems but none have thus far been reported for molecules with H2P2, H3SiP, and HSiP stoichiometries. We have addressed this issue by using the B3LYP/6-31+G(d,p) approach to find such stable structures. Final geometries were optimized at the CCSD(T)/cc-pvtz level for energies and were used for ELF and AIM analyses based on B3LYP/6-31+G(d,p) Kohn-Sham wavefunctions. In the case of HSiP a bridged structure with the hydrogen closer to phosphorus is found to be lower in energy than the linear HSiP molecules by some 10.2 kcal/mol. No other hydrogen bridged structures were encountered.