Intermolecular interactions in cluster anions

We present a broad-brush picture of the covalent and electrostatic interactions controlling the structures and stabilities of cluster anions and discuss how one should think about chemical bonding in these species. Accordingly, the review emphasises the broad general trends, which stem from the aggregate nature of clusters rather than from the individual chemistry of the compounds comprising the specific systems considered. The offered perspective relies on a coupled-monomers approach, which assumes first-order separability of the inter- and intra-monomer interactions. It effectively treats the cluster components as interlocking but self-contained building blocks. A Hückel-style formalism, adapted specifically to a mixed network of covalent and solvation interactions in cluster anions, offers general insight into the cooperation and competition between the multitudes of interactions implicated in solvated environments.