Giant Covalent Structures

This lesson covers giant covalent structures — substances where millions of atoms are bonded together by covalent bonds in a huge network. You need to know the structures and properties of diamond, graphite and silicon dioxide for the Edexcel GCSE Chemistry (1CH0) exam, and be able to explain their properties in terms of structure and bonding.

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What Are Giant Covalent Structures?

Giant covalent structures (also called macromolecular structures) are substances in which:

• All the atoms are bonded to each other by strong covalent bonds.
• The structure extends throughout the entire material — there are no individual molecules.
• Millions (or billions) of atoms are joined in a continuous network.

Because all the bonds are strong covalent bonds, giant covalent structures have very high melting and boiling points — a large amount of energy is required to break the many covalent bonds.

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Diamond

Diamond is an allotrope of carbon (a different structural form of the element carbon).

Structure