Graphene and fullerenes

• What are giant covalent substances made of?

  Many atoms joined together by covalent bonds
• What are the forms of carbon mentioned that have giant covalent structures?

  Diamond, graphite, and graphene
• What is graphene?

  • A form of carbon
  • Consists of a single layer of carbon atoms
  • Atoms are joined together in hexagonal rings
• What are fullerenes?

  • Molecules of carbon with hollow shapes
  • Structures based on hexagonal rings of carbon atoms
  • Include rings with five or seven carbon atoms
• What is diamond's structure?

  All atoms are bonded to four others in a giant tetrahedral network
• Why is diamond considered the hardest known natural substance?

  Due to its strong tetrahedral network structure
• What is the melting point of diamond?

  Very high
• How does graphite's structure differ from diamond's?

  Graphite has atoms bonded to three others in giant sheets
• What allows graphene to conduct electricity well?

  It has delocalised electrons that can move freely
• What makes graphene useful in electronics?

  Its high melting point and ability to conduct electricity
• What are the properties of graphene?

  • Very high melting point
  • Very strong
  • Conducts electricity well
  • Has delocalised electrons
• What is the structure of fullerenes based on?

  Hexagonal rings of carbon atoms
• What is buckminsterfullerene?

  A form of carbon consisting of 60 carbon atoms arranged in a hollow sphere
• What type of forces exist between molecules of buckminsterfullerene?

  Weak intermolecular forces
• Why does buckminsterfullerene have a low melting point?

  Weak intermolecular forces require little energy to overcome
• What are nanotubes?

  • Like a layer of graphene rolled into a cylinder
  • Have high length to diameter ratios
  • Strong in tension and resist being stretched
• What gives nanotubes their high tensile strength?

  Their structure and strong covalent bonds
• What is the relationship between nanotubes and graphene?

  Nanotubes are derived from graphene
• Why are nanotubes useful in nanotechnology and electronics?

  Because they are strong and conduct electricity
• What are the key differences between graphene, fullerenes, and diamond?

  • Graphene: single layer, conducts electricity, very strong
  • Fullerenes: hollow shapes, weak intermolecular forces, low melting point
  • Diamond: tetrahedral structure, hardest substance, very high melting point