Stable aluminum and chromium oxide clusters as precursors to nanoscale materials

It is shown that by using specific physical and chemical criterion, it is possible to identify clusters with interesting properties that are highly stable and fairly rigid so that they are likely to form extended structures maintaining their identity and properties. The first area involves the chemical control of the electronic affinity and magnetic behavior of chromium oxide clusters. Here, we show that fully coordinated Cr_nO_3n clusters are extremely stable and could form ionic molecules when combined with alkali atoms. The second area relates to aluminum based clusters where it has been shown that by reacting aluminum clusters with HI, it is possible to form very stable Al₁₃I^- clusters. Here we discuss why such a reaction with HCl does not produce, Al₁₃Cl^- and how the stability of these clusters is governed by electronic shell structure of a nearly free electron system.