AQA GCSE Chemistry

Revision Notes

2.3.1 Diamond

Diamond: Structure & Bonding

  • Diamond and graphite are  allotropes of carbon
  • Both substances contain only carbon atoms but due to the differences in bonding arrangements they are physically completely different
  • In diamond, each carbon atom bonds with four other carbons, forming a tetrahedron
  • All the covalent bonds are identical, very strong and there are no intermolecular forces

Diamond structure, IGCSE & GCSE Chemistry revision notes

Diagram showing the structure and bonding arrangement in diamond

Exam Tip

You should be able to relate the physical properties of diamond to its bonding arrangement and structure.

Properties of Diamond

  • Diamond has the following physical properties:
    • It does not conduct electricity
    • It has a very high melting point
    • It is extremely hard and has a density of 3.51 g/cm3 – a little higher than that of aluminium
  • All the outer shell electrons in carbon are held in the four covalent bonds around each carbon atom, so there are no freely moving charged particles to the current
  • The four covalent bonds are very strong and extend in a giant lattice, so a very large amount of heat energy is needed to break the lattice
  • Diamond ́s hardness makes it very useful for purposes where extremely tough material is required
  • Diamond is used in jewellery and for coating blades in cutting tools
  • The cutting edges of discs used to cut bricks and concrete are tipped with diamonds
  • Heavy-duty drill bits and tooling equipment are also diamond tipped

Exam Tip

Diamond is the hardest naturally occuring mineral, but it is by no means the strongest. Students often confuse hard with strong, thinking it is the opposites of weak. Diamonds are hard, but brittle – that is, they can be smashed fairly easily with a hammer. The opposite of saying a material is hard is to describe it as soft.

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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