# Explain why graphite can conduct electricity but diamond cannot, despite both being giant covalent structures made entirely of carbon atoms.

> OCR GCSE Chemistry A: Gateway Science (J248) — C2.3 Properties of materials · Explain · 4 marks

> Graphite and diamond are both allotropes of carbon used in very different industrial applications. Graphite is used in electrodes, whilst diamond is used as an electrical insulator in cutting tools.

## Mark scheme (4 marks)

1. In graphite, each carbon atom forms three covalent bonds (with three other carbon atoms), leaving one electron per carbon atom not used in bonding.
2. This leaves a delocalised electron per carbon atom that is free to move and carry charge, allowing graphite to conduct electricity.
3. In diamond, each carbon atom forms four covalent bonds with four other carbon atoms.
4. All electrons in diamond are involved in covalent bonds, so there are no free/delocalised electrons to carry charge, meaning diamond cannot conduct electricity.

## Key terms

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

## Related

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