giant covalent

• properties of graphite

  • soft
  • very high melting point
  • very high boiling point
  • insoluble in water
  • good electrical conductor
• diamond properties

  • 3D giant lattice, millions of carbon atoms
  • each carbon has four strong covalent bonds in every direction
  • can't conduct electricity, no delocalised electrons, evert electron used in 4 bonds
  • has a high melting and boiling point as it would take a lot of energy to separate the bonds
• graphite properties

  • sheets of hexagons, in a giant lattice, layers slide over each other
  • each carbon has three bonds forming flat layers of hexagons
  • does conduct electricity as it has one free electron per carbon can move throughout the structure and carry charge
  • high melting and boiling point as it takes a lot of energy to separate the bonds
• silicon dioxide (giant covalent) properties?

  • less high boiling and melting point that graphite and diamond but still high, four covalent bonds but not to other carbons
  • in SiO2 every electron is taken up in covalent bonds, no delocalised electrons
  • strong covalent bonds join each siliconcatom to four oxygens, each silicon atom inside the structure is covalently bonded in a 3D arrangement