# Explain why silicon dioxide has a very high melting point.

> Cambridge International IGCSE Chemistry (0620) — 2.6 Giant covalent structures · Explain · 4 marks

> Silicon dioxide is used to line the inside of furnaces because it can withstand extremely high temperatures.

## Mark scheme (4 marks)

1. Silicon dioxide has a giant covalent structure
2. There are many strong covalent bonds throughout the structure
3. A large amount of energy is required to break these bonds
4. Therefore a very high temperature is needed to melt it

## Key terms

- [melting point](https://www.gradenine.co.uk/glossary/melting-point)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-silicon-dioxide-has-a-4a3144a0) · Published by Druglandscape Ltd.