# Graphite and diamond are both giant covalent structures made entirely of carbon atoms, yet they have very different properties. Explain why graphite can conduct electricity whilst diamond cannot, and explain why both substances have high melting points.

> OCR A-Level Chemistry B: Salters (H433) — 2.4 Electrons, bonding and structure · Explain · 5 marks

> Graphite is used as an electrode material in electrolysis because it conducts electricity. Diamond, despite also being made of carbon, is used as a cutting tool rather than an electrical conductor.

## Mark scheme (5 marks)

1. In graphite, each carbon atom forms three covalent bonds (with three other carbon atoms)
2. Graphite has one delocalised electron per carbon atom which is free to move and carry charge
3. In diamond, each carbon atom forms four covalent bonds so there are no delocalised electrons
4. Both structures contain many strong covalent bonds throughout the structure
5. A large amount of energy is needed to break these covalent bonds, resulting in high melting points

## Key terms

- [giant covalent structure](https://www.gradenine.co.uk/glossary/giant-covalent-structure)
- [graphite](https://www.gradenine.co.uk/glossary/graphite)
- [diamond](https://www.gradenine.co.uk/glossary/diamond)

## Related

- [Revision notes for OCR A-Level Chemistry B: Salters (H433)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/graphite-and-diamond-are-both-giant-c630e5bf) · Published by Druglandscape Ltd.