The last decade has seen remarkable progress in the development of new materials based on transition-metal ions and organic ligands, often termed as coordination polymers (networks) or metal–organic frameworks. Although this relatively new field of chemistry aims at the discovery and synthesis of new materials for practical applications emphasizing their functional aspects, it would be difficult to achieve a true advance without understanding the structural aspects of such materials at a molecular or an atomic resolution. Recent reviews on the framework topologies and other geometrical characteristics of network solids reflect this importance. As the number of infinite network structures based on molecular building blocks increases, it becomes easier to analyze and categorize their framework topologies. It appears that for the majority of 3D metal–organic framework structures, there are well-known prototypes in metallic or binary inorganic solids. For example, diamond-related nets composed of one or two kinds of tetrahedral nodes and linear linkers are the most common, and a primitive cubic net (a-Po) based on octahedral nodes with linear linkers is also frequently observed. Other 3D structures have recently been reported to have the following topologies: boracite, CdSO4, [5] CaB6, [6] feldspar, NbO, perovskite, Pt3O4, [10]