Allotropes of Carbon

This lesson covers the different structural forms (allotropes) of carbon — diamond, graphite, graphene, fullerenes and carbon nanotubes. Understanding their structures, properties and uses is required by the Edexcel GCSE Chemistry (1CH0) specification.

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What Are Allotropes?

Allotropes are different structural forms of the same element in the same physical state. The atoms are bonded together in different arrangements, giving each allotrope different physical properties.

Carbon has several allotropes, including diamond, graphite, graphene, fullerenes (e.g. buckminsterfullerene, C₆₀) and carbon nanotubes.

Exam Tip: Don't confuse allotropes with isotopes. Allotropes = same element, different structures. Isotopes = same element, different numbers of neutrons.

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Diamond

(Covered in detail in the previous lesson — brief recap here.)

• Each carbon bonded to 4 others in a tetrahedral arrangement.
• Giant covalent structure — rigid 3D lattice.
• Very hard, very high melting point.
• Does not conduct electricity (no delocalised electrons).
• Used in cutting tools, drill bits, jewellery.

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Graphite

(Covered in detail in the previous lesson — brief recap here.)