Giant Covalent substances

• Tetrahedral structure (four bonds)
• Very high melting poing (strong covalent bonds)
• Very strong (strong covalent bonds)
• Doesn't conduct electricity (all electrons used for bonding)

• Very high melting point
• Soft (arranged in layers that can slide)
• Conducts electricity (one free electron)
• Hexagonal structure

Graphite conducts electricity, but diamond does not, explain why. (3 marks)

In diamond, all electrons are used up in covalent bonds. However, in graphite, only three electrons are used in bonds. There is one free electron. This electron can carry electricity between the layers.