More of the “Fullercages”

All complex intermetallic phases have been searched for their structural building principles, in particular for the occurrence of fullercages, i.e., fullerene‐like cluster shells. The diversity of inter‐metallics featuring compounds of this kind is discussed as well as the geometrical building principles characteristic for their endohedral constituting clusters. Typically, the core cluster corresponds to a polyhedron of the Frank‐Kasper ( FK ) type, which is surrounded by a fullerene‐like shell dual to it. The next cluster shell is again a FK polyhedron followed by a fullerene‐like shell, and this can be repeated. The chemical composition of these complex intermetallics (CIMs) is quite diverse, mostly combining electropositive elements from groups 1–4 with electronegative elements of groups 7–14, for instance Li‐Ga or RE ‐Cd ( RE = rare earth element). However, also less‐common combinations from elements of groups 1 and 2, such as Li‐Ba, or from groups 11 and 12, such as Cu‐Cd, are known.