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Carbon can exist in many different forms. Carbon can exist in these forms:
- graphite
- diamond
- C60 fullerene
Different forms of carbon have different structures and properties.
Graphite

Structure and Bonding
- Graphite forms a giant covalent structure.
- Each carbon atom is covalently bonded to 3 other carbon atoms.
- Carbons form layers of hexagonal rings.
- The layers are joined by weak intermolecular forces.
- Since only 3 outer electrons are used to form covalent bonds, 1 electron from each carbon atom becomes delocalised.
Properties
- Slippery
- The layers are held by weak intermolecular forces, so layers can easily slide over each other.
- High melting and boiling point
- Graphite forms a giant covalent structure with many strong covalent bonds. A lot of thermal energy is needed to break the bonds.
- Conductor of electricity
- The delocalised electron can move freely within each layer, so graphite can conduct electricity.
Uses
- lubricant
- electrodes for electrolysis
Diamond

Structure
- Diamond forms a giant covalent structure.
- Each carbon atom is covalently bonded to 4 other carbon atoms
Properties
- Hard
- Since diamond is a rigid structure held by strong covalent bonds, it is one of the world's hardest materials.
- High melting and boiling point
- Diamond forms a giant covalent structure with many strong covalent bonds. A lot of thermal energy is needed to break the bonds.
- Does not conduct electricity
- All 4 outer shell electrons of carbon are used to form covalent bonds, so there is no delocalised electron to conduct electricity.
Uses
- cutting tool
- jewelry
C60 Fullerene

Structure and Bonding
- C60 fullerene has a molecular structure formed by 60 carbon atoms. (It is not a giant covalent structure!!)
- The shape of the molecule is spherical.
- Each carbon atom is covalently bonded to 3 other carbon atoms.
- Since only 3 outer electrons are used to form covalent bonds, 1 electron from each carbon atom becomes delocalised.
- There are weak intermolecular forces between each fullerene molecule.
Properties
- Soft and slippery
- The weak intermolecular forces between fullerene molecules are broken down easily, so fullerene is soft and slippery.
- Low melting and boiling point
- Only a small amount of heat energy is needed to overcome to weak intermolecular forces between molecules.
- Conductor of electricity
- The delocalised electron is mobile, so fullerene can conduct electricity.
Uses
- Drug delivery system in the body
- Lubricant