Figure : Simplified model to show the difference between dimeric and monomeric oxo clusters. For the dimeric species three different type of ligands exist, chelating, bridging and inter-cluster bridging. The latter connect two metal oxo octaeders to form the dimer. For the monomeric species no inter-cluster ligand can found. These clusters either have only bridging ligands or a combination of bridging and chelating ligands. Note that for simplicity no hydrogens are showns and ligands are shortened to the acetate form. Also the oxygen atoms on the cluster core were omitted.