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Very large molecules

Graphene

is an of carbon. Its structure resembles a single layer of . Graphene has a very high and is very strong because of its large regular arrangement of carbon joined by . Like graphite, it electricity well because it has that are free to move across its surface.

Fullerenes

A is a allotrope of carbon. Two examples of fullerenes are and .

Nanotubes

A nanotube resembles a layer of graphene, rolled into a tube shape. Nanotubes have high , so they are strong in and resist being stretched. Like graphene, nanotubes are strong, and they conduct electricity because they have delocalised electrons.

Covalent structure of a nanotube
Figure caption,
Nanotubes can be several millimetres long but only a few nanometres wide

Buckyballs

Buckyballs are spheres or squashed spheres of carbon atoms. They are made up of large molecules so are not classed as . Weak exist between buckyballs. These need little to overcome, so substances consisting of buckyballs are slippery and have lower melting points than graphite or .

Covalent structure of buckminsterfullerene
Figure caption,
Buckminsterfullerene has 60 carbon atoms joined by covalent bonds