A fullerene is an allotrope of carbon whose molecules consist of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecules may have hollow sphere- and ellipsoid-like forms, tubes, or other shapes.
C60 fullerite (bulk solid C60).
Fullerite (scanning electron microscope image)
C 60 in solution
C 60 in extra virgin olive oil, showing the characteristic purple color of pristine C 60 solutions
Carbon is capable of forming many allotropes due to its valency. Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been discovered and researched, including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger-scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperatures or extreme pressures. Around 500 hypothetical 3‑periodic allotropes of carbon are known at the present time, according to the Samara Carbon Allotrope Database (SACADA).
Computer models of stable nanobud structures
A large sample of glassy carbon.
The K4 crystal
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.
