Graphene and fullerenes
A form of carbon consisting of a single layer of carbon atoms joined together in hexagonal rings. and Molecules of carbon with hollow shapes. Their structures are based on hexagonal rings of carbon atoms. are forms of carbon. Their structures are different from those of A form (allotrope) of pure carbon in which all the atoms are bonded to four others in a giant tetrahedral network structure which is very strong. Diamond is the hardest known natural substance, has a very high melting point and does not conduct electricity. and A form of pure carbon in which all the atoms are bonded to three others in giant sheets which can slide over each other., which are also forms of carbon.
Graphene
Graphene is a single layer of graphite. The strong A bond between atoms formed when atoms share electrons to achieve a full outer shell of electrons. between the carbon atoms mean that graphene:
- has a very high The temperature at which a solid changes into a liquid as it is heated.
- is very strong
Like graphite, graphene conducts electricity well because it has Electrons that are not associated with a particular atom, eg in a metal, outer electrons can be free to move through the solid. Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. that are free to move across its surface.
These The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point. make graphene useful in electronics and for making Material made from two or more different materials with contrasting properties..
Fullerenes
Fullerenes are A collection of two or more atoms held together by chemical bonds. of carbon atoms with hollow shapes. Their structures are based on hexagonal rings of carbon atoms joined by covalent bonds. Some fullerenes include rings with five or seven carbon atoms. Two examples of fullerenes are A form of carbon consisting of molecules made up of 60 carbons arranged to form a hollow sphere. and Long cylindrical molecules made from carbon atoms joined together by covalent bonds..
Buckminsterfullerene
Buckminsterfullerene was the first fullerene to be discovered. Its molecules are made up of 60 carbon atoms joined together by strong covalent bonds. Molecules of C60 are spherical.
There are weak Weak attractive forces between molecules. When a simple molecular substance melts or boils, it is the intermolecular forces that are broken (not the covalent bonds in each molecule). between molecules of buckminsterfullerene. These need little energy to overcome, so buckminsterfullerene is slippery and has a low melting point.
Nanotubes
A nanotube is like a layer of graphene, rolled into a cylinder. The length of a nanotube is very long compared to its width, so nanotubes have high length to diameter ratios.
Nanotubes have high The tension a material can withstand without breaking., so they are strong in Pulling force exerted by each end of an object such as a string or rope. and resist being stretched. Like graphene, nanotubes are strong and conduct electricity because they have delocalised electrons.
These properties make nanotubes useful for nanotechnology, electronics and specialised materials.