# Magnesium oxide is an ionic compound used as a lining in furnaces that operate at very high temperatures. Explain why magnesium oxide is suitable for this use, in terms of its structure and bonding.

> OCR A-Level Chemistry A (H432) — 2.4 Electrons, bonding and structure · Explain · 5 marks

> Magnesium oxide is formed when magnesium atoms lose two electrons to oxygen atoms. It is used to line industrial furnaces because it can withstand extremely high temperatures without melting.

## Mark scheme (5 marks)

1. Magnesium oxide is an ionic compound / contains ions
2. Magnesium forms a positive ion and oxygen forms a negative ion (or Mg²⁺ and O²⁻ stated)
3. There are strong electrostatic forces of attraction between the oppositely charged ions
4. Magnesium oxide has a giant ionic structure / the ions are arranged in a lattice
5. A large amount of energy is needed to break these strong electrostatic forces, so magnesium oxide has a very high melting point / is suitable for use at very high temperatures

## Key terms

- [ionic compound](https://www.gradenine.co.uk/glossary/ionic-compound)
- [ion](https://www.gradenine.co.uk/glossary/ion)

## Related

- [Revision notes for OCR A-Level Chemistry A (H432)](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/magnesium-oxide-is-an-ionic-compound-d7719dcb) · Published by Druglandscape Ltd.