Carbon Nano-tubes & Graphene
Graphene
- Graphene consists of a single layer of graphite which is a sheet of carbon atoms covalently bonded forming a continuous hexagonal layer
- It is essentially a 2D molecule since it is only one atom thick
- It has very unusual properties make it useful in fabricating composite materials and in electronics
Diagram to show the structure and bonding in graphene
Graphene is a single layer of graphite
Linking the Bonding & Properties
- Graphene is extremely strong but also amazingly light
- It would take an elephant with excellent balance to break through a sheet of graphene
- It is very strong due to its unbroken pattern and the strong covalent bonds between the carbon atoms
- Even when patches of graphene are stitched together, it remains the strongest material out there
- Graphene conducts heat and electricity
- It has delocalised electrons
- These are free to move and carry a charge
Carbon Nanotubes
- Graphene can also be rolled into a cylinder to produce an interesting type of fullerene called a nanotube
- These have high tensile strength but a low density and are resistant to breaking or stretching
- As in graphene, nanotubes can also conduct electricity which makes them useful in composites and specialised materials, electronics and nanotechnology
- Carbon nano-tubes have a much smaller scale structure than carbon fibres and are not what is used in the manufacture of bikes and tennis rackets
Diagram to show the structure of a carbon nanotube
A nanotube can be produced from a rolled sheet of graphene
Linking the Bonding & Properties
- Carbon nanotubes conduct electricity
- Each carbon is bonded to three other carbon atoms leaving one electron per atom unbonded
- These delocalised electrons are free to move and carry a charge
- Carbon nanotubes have a high melting point
- There are strong covalent bonds between carbon atoms
- These need lots of energy to overcome
- Carbon nanotubes have a low density and are very strong
- Each carbon atom is joined together by strong covalent bonds
- These require lots of force to break
Examiner Tip
Common exam questions ask you to explain the properties of different substances so it is worth spending the time learning these!
