Cluster compounds help to bridge the gap between atom and solid

We discuss in this paper the possibilities to calculate electronic structure of the metal atom cluster compounds (CC) and present some interesting results from binuclear and hexanuclear cluster prototypes. The aim of this work is to show that quantum chemistry of CC has an extraordinary potential to provide:(1) interesting examples of the highly dispersed metallic state (only quantum chemistry has developed a model to bridge the whole gap between atom and solid, the analytic cluster model),(2) simple models of local bulk situations (e.g. behaviour of impurity atoms), developing cluster-bulk analogy,(3) simple models of local surface phenomena (e.g. chemisorption processes), developing cluster-surface analogy. The most important point is to initiate knowledge transfer between complex chemistry, surface chemistry, field of highly dispersed metals and metal physics.