heterofullerene

Any compound formally derived from a fullerene by replacing one or more carbon atom by a heteroatom.

"Such heterofullerenes are expected to have applications
in superconductivity."

megaherbivore

Any very large herbivore that weighs more than 1000kg.

"Elephants are classified as megaherbivores and consume up to 150 kg of plant matter per day."

fullerene

An allotrope of carbon with fused rings of five to seven atoms and a closed or partially closed mesh formed by carbon atoms joined by single and double bonds. The molecule may have the form of a hollow spherical, ellipsoid, tube, or something else entirely.

If collapse to a fullerene occurs before the cluster has accumulated 60 atoms, buckminsterfullerene can not be produced.