Britannica Sources used in this answer

What are fullerenes and buckyballs made of?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A labeled diagram of the periodic table entry for carbon, showing its atomic number 6, symbol C, electron configuration, atomic weight range, solid physical state, hexagonal crystal structure, and weakly acidic oxide properties. Color coding and icons indicate it is a nonmetal, solid at room temperature, with hexagonal structure and weak acidity. — carbon Carbon and its properties.

Fullerenes and buckyballs are composed entirely of carbon atoms.12

A fullerene is a category of hollow carbon molecules that can form either closed cages, known as "buckyballs," or cylinders, known as carbon nanotubes. The most well-known buckyball, buckminsterfullerene ( $C_{60}$ ), consists of 60 carbon atoms joined by single and double bonds to form a hollow sphere. This structure resembles a soccer ball, featuring 12 pentagonal and 20 hexagonal faces.12

While these molecules are primarily made of carbon, researchers have also created "endohedral" complexes, where other atoms or small molecules—such as helium or various metals—are physically trapped inside the carbon cage.2