In chemistry, a metallofullerene is a molecule composed of a metal atom trapped inside a fullerene cage. These kinds of molecules hold a lot of potential in the advancement of materials design.
Simple metallofullerenes consist of a fullerene cage, typically C80, with one or two metal atoms trapped inside. Recently, research has produced metallofullerenes that enclose small clusters of atoms, such as Sc3N@C80, Y3N@C80, and Sc3C2@C80. The '@' symbol in the formula indicates that the atom(s) are encapsulated inside the cage, rather than being chemically bonded to it.
Fullerenes in a variety of sizes have been found to encapsulate metal atoms in this way.