2) Graphite

•  It also has a giant covalent structure and a very high melting point.
• Each carbon atom forms three covalent bonds with other carbon atoms.
• This results in a layered, hexagonal structure.
• The layers are held together by weak intermolecular forces.
• This means that the layers can slide past each other, making graphite soft and slippery.
• One electron from each carbon atom in graphite is delocalised.
• These delocalised electrons allow graphite to conduct heat and electricity.
• Silicon dioxide (or silica, SiO2) has a lattice structure similar to diamond:

  • Each oxygen atom is joined to two silicon atoms.
  • Each silicon atom is joined to four oxygen atoms.