allotropes of carbon

• what are allotropes?

  different structural forms of the same element in the same physical state
• what are the properties of diamond structure?

  -high melting point as covalent bonds are strong so take lots of energy to break

  -doesn’t conduct electricity as it has no free electrons or ions
• why can the layers of the graphite structure slide over each other?

  there aren’t any covalent bonds between the layers, only held together weakly, so free to move over each other making graphite soft and slippery(ideal lubricating material)
• what are the properties of graphite structure?

  -high melting point, covalent bonds need lots of energy to break

  -conducts electricity and thermal energy, only three out of four electrons are used in bonds so each atom has one delocalised electrons that is free to move through the structure
• what is graphene?


  a single layer of graphite, sheet of carbon atoms joined together in hexagons
• what are the properties of graphene?

  -one atom thick, making it two dimensional substance

  -covalent bonds make it strong but also very lightweight
• what shape do fullerenes form?

  molecules of carbon that form tubes and hollow spheres
• what shape are fullerenes mainly made up of?

  carbon atoms arranged in hexagons, sometimes contain pentagons and heptagons
• what are fullerenes used for?

  to ‘cage’ other molecules by forming a structure around another atom or molecule which is then trapped inside, e.g. could be for delivering a drug into the body
• what was the first fullerene to be discovered?

  buckminster fullerene, got a molecular formula, C60 and forms hollow sphere
• what are the tubes called that fullerenes can form?

  nanotubes, tiny carbon cylinders
• what are the properties of a nanotube?

  -ratio between the length and diameter of nanotubes is very high

  -conduct both electricity and thermal energy

  -have high tensile strength(don’t break when stretched)