Structure and bonding of carbon

• Diamond:

  • Each carbon is joined to 4 other carbons covalently
  • Very hard, has a very high melting point and does not conduct electricity
• Graphite:

  • Each carbon is covalently bonded to 3 other carbons, forming layers of hexagonal rings with no covalent bonds between the layers
  • Layers can slide over each other due to weak intermolecular forces, making graphite soft and slippery
  • One electron from each carbon atom is delocalised, making graphite similar to metals and able to conduct electricity
• Graphene:

  • Single layer of graphite
  • Useful in electronics and composites
  • Very strong because atoms within its layers are tightly bonded and elastic because the planes of atoms can flex relatively easily without breaking apart
• Fullerenes:

  • Carbon can form fullerenes with different numbers of carbon atoms
  • Molecules with hollow shapes based on hexagonal rings of carbon atoms, may contain rings with five or seven carbon atoms
  • First fullerene discovered was Buckminsterfullerene (C60) with a spherical shape
• Carbon nanotubes:

  • Cylindrical fullerenes with very high length to diameter ratios
  • Useful for nanotechnology, electronics, and materials
• Examples of uses:

  • Can be used as lubricants, to deliver drugs in the body, and as catalysts
  • Nanotubes can reinforce materials, for example, tennis rackets