Fullerenes & Graphene (Edexcel GCSE Chemistry) : Revision Note

Fullerenes & Graphene

C₆₀ fullerene

• Fullerenes are a group of carbon allotropes which consist of molecules that form hollow tubes or spheres

• The first fullerene to be discovered was Buckminsterfullerene, which is affectionately referred to as a “buckyball”

  • In Buckminsterfullerene, 60 carbon atoms are joined together forming a hollow sphere

  • The molecule is made of 20 hexagons and 12 pentagons, arranged like a football (soccer ball)

The structure and bonding in C₆₀ fullerene - the football shaped molecule

Properties of C₆₀ fullerenes:

• Electrical insulator

  • Each carbon atom forms three covalent bonds, with some delocalised electrons

  • Howver, the electrons are not delocalised across the entire structure, so C₆₀ does not conduct electricity well

• Targeted drug delivery systems

  • The hollow spherical shape allows C₆₀ molecules to encapsulate other molecules, transporting them to specific sites in the body

• Catalyst support

  • The large surface area allows catalyst particles to be attached to the surface, making them more accessible to reactants

• Lubricant

  • The spherical shape and weak intermolecular forces allow them to roll and slide, reducing friction

Graphene

• Graphene is a single layer of graphite, one atom thick, made entirely of carbon atoms covalently bonded in a hexagonal lattice.

  • It is essentially a 2D molecule since it is only one atom thick

• Graphene has a range of unusual properties that make it useful in composite materials and electronics

Graphene is a truly remarkable material that has some unexpected properties

Properties of graphene:

• Strength

  • Strong covalent bonds form an unbroken hexagonal network, making graphene extremely strong, even when layers are stitched together

• Lightweight

  • Being only one atom thick, graphene is very light relative to its strength

• Conductivity

  • Each carbon atom in graphene forms three covalent bonds and has one delocalised electron

  • The delocalised electrons are free to move across the surface, allowing graphene to conduct electricity up to 200 times faster than silicon

  • It is also an excellent conductor of heat

• Flexibility

  • The strong carbon–carbon bonds allow the sheet to be bent, twisted, or stretched without breaking, giving graphene its flexibility

• Transparency

  • Graphene absorbs only 2.3% of visible light, making it nearly transparent

  • This gives it potential for use in future flexible touchscreens and display technology