Diamond (and Silicon)
- Each Carbon atom forms 4 strong covalent bonds with other atoms to give a tetrahedral structure.
High melting and boiling points
- A lot of energy is required to break the many strong bonds, hence the high melting and boiling points.
- The many strong bonds each require a large force to break them.
Doesn't conduct electricity
- No free electrons to carry a current when a potential is applied.
- Each Carbon atoms forms 3 strong covalent bonds with other Carbon atoms, resulting in a layered structure.
- One spare electron is delocalised between the layers.
- The layers are held together by weak intermolecular forces.
High Melting and Boiling points
- The many strong bonds require a lot of energy to break, hence the high melting and boiling points.
- Little force is needed to overcome the weak intermolecular forces.
- The free delocalised electron is able to carry a current when a potential is applied.
That is all!