Chemistry
Graphene and fullerenes Learning objectives: • explain the properties of graphene in terms of its structure and bonding • recognise graphene and fullerenes from their bonding and structure • describe the uses of fullerenes, including carbon nanotubes.
KEY WORDS cylindrical fullerene graphene nanotube
Carbon does not only exist in the structures of diamond and graphite but also as ball-shaped or cylindricalshaped structures called fullerenes. The structure of the first one to be discovered looked like a football and was called Buckminsterfullerene and other smaller ones are called ‘buckyballs’. The tiny cylindrical tubes are fullerene nanotubes.
Graphene and fullerenes Graphene is a single layer of graphite and so is one atom thick. It has properties that make it useful in electronics and composites. It is made up of hexagonal rings of carbon atoms connected to one another by strong bonds.
Figure 2.48 Graphene – hexagonal rings of carbon one atom thick
Carbon atoms in rings can also form hollow 3D shapes. The first one found had 60 carbon atoms. It had rings of six carbon atoms and rings of five carbon atoms. It was named Buckminsterfullerene. Structures of this type are known as fullerenes. Fullerenes are molecules of carbon atoms with hollow shapes. The structure of fullerenes is based on hexagonal rings of carbon atoms but they may also contain rings with five or seven carbon atoms. Buckminsterfullerene (C60) has a spherical shape, other fullerenes can be in the shapes of spheres or tubes.
Figure 2.49 A traditional football can be used as a molecular model for C60.
There are already a number of medical uses for them but their potential use is still being researched. 1
Compare the structures of graphene and fullerenes.
Carbon nanotubes
DID YOU KNOW?
Fullerenes can be used for drug delivery into the body, as lubricants, and as catalysts. They can act as hollow cages to trap other molecules. This is how they can carry drug molecules around the body and deliver them to where they are needed, and trap dangerous substances in the body and remove them.
C60 was named after the architect Buckminster Fuller as it looked like the geodesic domes that he created.
Carbon can also be used to make very small structures called nanotubes. Carbon nanotubes are cylindrical fullerenes. They have very high length to diameter ratios. Their properties make them useful for nanotechnology, electronics and materials. Some of their special properties are: • high tensile strength
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AQA GCSE Chemistry for Combined Science: Trilogy: Student Book
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