Metallo-Carbohedrenes: Formation of Multicage Structures

An unusual structural growth pattern has been found in the system of Zr m C n , in which multicage structures are formed. The experimental evidence shows that the first cage closes at Zr 8 C 12 . Surprisingly, subsequent cluster growth does not lead to the enlargement of the cage size as it usually does in the case of pure carbon clusters and water clusters, for example. Rather, multicage structures are developed, that is, a double cage at Zr 13 C 22 and Zr 14 C 21/23 , a triple cage at Zr 18 C 29 , and a quadruple cage at Zr 22 C 35 . This feature distinguishes the class of metallo-carbohedrenes from the regular doped fullerenes.