The bonding situation in mercury-alkali diatomics HgA (2Σ+) (A = Li, Na, K, Rb) has been investigated employing the relativistic all-electron method Normalized Elimination of the Small Component (NESC), CCSD(T), and augmented VTZ basis sets. Although Hg,A interactions are typical of van der Waals complexes, trends in calculated De values can be explained on the basis of a 3-electron 2-orbital model utilizing calculated ionization potentials and the De values of HgA+(1Σ+) diatomics. HgA molecules are identified as orbital-driven van der Waals complexes. The relevance of results for the understanding of the properties of liquid alkali metal amalgams is discussed.
Kraka, E., & Cremer, D. (2008). Bonding in mercury-alkali molecules: Orbital-driven van der Waals complexes. International Journal of Molecular Sciences, 9(6), 926–942. https://doi.org/10.3390/ijms9060926