AQA GCSE Chemistry

Revision Notes

2.3.2 Graphite

Graphite: Structure & Bonding

  • Each carbon atom in graphite is bonded to three others 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
  • 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, IGCSE & GCSE Chemistry revision notes

Diagram showing the structure and bonding arrangement in graphite

Properties of Graphite

  • Graphite has the following physical properties:
    • It conducts electricity and heat
    • It has a very high melting point
    • It is soft and slippery and less dense than diamond (2.25 g/cm3)
  • Graphite ́s weak intermolecular forces make it a useful material
  • It is used in pencils and as an industrial lubricant, in engines and in locks
  • It is also used to make inert electrodes for electrolysis, which is particularly important in the extraction of metals such as aluminium

Exam Tip

Don’t confuse pencil lead with the metal lead – they have nothing in common. Pencil lead is actually graphite, and historical research suggests that in the past, lead miners sometimes confused the mineral galena (lead sulfide) with graphite; since the two looked similar they termed both minerals ‘lead’.

The word graphite derives from the Latin word ‘grapho’ meaning ‘I write’, so it is a well named mineral!

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.
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