C2.6 Giant covalent structures

Describe the giant covalent structure of graphite

• Each carbon atom is bonded to 3 other carbon atoms, leaving 1 free, delocalised electron per carbon atom

  • It can conduct electricity

• Arranged in layers which can slide over each other because they are joined by weak intermolecular forces, but the covalent bonds between carbon atoms are strong

• High melting and boiling point

Describe the giant covalent structure of diamond

• Each carbon atom is bonded to 4 other carbon atoms

  • No free electrons = cannot conduct electricity

• No intermolecular forces, very strong covalent bonds

• Hard

• High melting and boiling point

Relate the structure and bonding of graphite to its uses

• Uses: lubricant and electrode

  • Lubricant: weak intermolecular forces between layers allow carbon atoms to slide over each other, making it very slippery and smooth

  • Electrode: good electrical conductor since it has delocalised ions which can move and carry an electrical charge

Relate the structure and bonding of diamond to its uses

• Uses: cutting tools

  • Cutting tools: diamond is extremely hard and dense, making it an excellent cutting tool