Carbon Structures and Their Properties

Structure and Bonding of Carbon

Diamond
  • Each carbon atom is covalently bonded to 4 other carbon atoms.
  • Known for its:
    • Very hard structure
    • High melting point
    • Inability to conduct electricity
Graphite
  • Each carbon atom forms covalent bonds with other carbons, creating layers of hexagonal rings.
  • Key characteristics:
    • No covalent bonds between layers, only intermolecular forces.
    • Layers can slide over each other, making graphite soft and slippery.
    • One electron from each carbon is delocalized, which allows for electrical conductivity.
Graphene
  • Composed of single layers of graphite.
  • Properties:
    • Extremely strong due to tight bonding of atoms within layers.
    • Flexible and useful in electronic applications.
Fullerenes
  • Carbon can form fullerenes, which exhibit a variety of shapes and sizes based on the number of carbon atoms.
    • Buckminsterfullerene (C60): First discovered fullerene, spherical shape.
    • Carbon Nanotubes: Cylindrical fullerenes with a high length-to-diameter ratio, making them useful in electronic and material applications.

Examples of Uses

  • Fullerenes and graphene are utilized in:
    • Lubricants
    • Drug delivery systems in the body
    • Catalysts
    • Reinforcement materials (e.g., in tennis rackets)

Metals

  • Metals possess giant structures of atoms with strong metallic bonding.
  • Characteristics include:
    • High melting and boiling points due to the strong bonding.
    • Layers of atoms can slide over one another, allowing for malleability.
Alloys
  • Alloys are comprised of two or more different types of metals, creating varying atomic sizes that disrupt the layers in the structure.
  • Benefits of alloys:
    • Harder than pure metals.
    • Good electrical conductors, as delocalized electrons can carry charge.
    • Good thermal conductors, energy is transferred by delocalized electrons.

Polymers

  • Composed of very large molecules consisting of long chains of repeating units.
  • Atoms in polymers are linked by covalent bonds, providing versatility in structure and functionality.