Theoretical investigation on the covalence in AgRnX and XAgRn (X = F - I)

CCSD(T) calculations were performed to investigate the stabilities and interaction mechanisms of the AgRnX and XAgRn (X = F - I) series. Dissociation energies and frontier orbital properties demonstrate an increased trend of stabilities. Ag spd hybrids and Rn/X sp hybrids come into the σ_Ag-Rn and σ_Ag-X bonding orbital. The nature of Ag-Rn, Ag-X and Rn-X interactions were investigated by atoms in molecules (AIM) theory. The negative energy density and positive Laplacian values, as well as small electron densities at bond critical points (BCPs), characterize the moderate strength with partial covalence of interactions. BCP properties (-G/V and G/ρ), electron density deformations and natural resonance theory (NRT) results display increased covalence down the periodic table.