Graphite Structure (AQA GCSE Chemistry)

Graphite structure

• Each carbon atom in graphite is able to form three covalent bonds to other carbon atoms forming layers of hexagons, leaving one free electron per carbon atom

• These free electrons migrate along the layers and are free to move and carry charge, hence graphite can conduct electricity

• Freely moving electrons are called delocalised electrons - that is, the opposite of localised - they are not confined to any particular place

• The covalent bonds within the layers are very strong, but the layers are attracted to each other by weak intermolecular forces, so the layers can slide over each other making graphite soft and slippery

Graphite structure

Diagram showing the structure and bonding arrangement in graphite

Properties of graphite

• Graphite conducts electricity 

  • Each carbon atom is bonded to three others leaving one free electron per carbon atom 

  • These free (delocalised) electrons exist in between the layers

  • They are free to move through the structure and carry charge

• Graphite has a high melting point

  • Graphite has a giant covalent structure

  • There are strong covalent bonds between the carbon atoms

  • These need lots of energy to break 

• Graphite is slippery 

  • Graphite is arranged in layers

  • Although the atoms within the layers are joined by strong covalent bonds, the layers have only weak intermolecular forces between them

  • As a result the layers can slide over each other

  • This property allows graphite to be used in pencils and as an industrial lubricant

• Graphite can be used to make inert electrodes for electrolysis, which is particularly important in the extraction of metals such as aluminium