- Crystal Structure
- Giant Covalent (macromolecular)
- High melting and boiling points because the atoms are held together by strong covalent bonds. For the the molecule to melt, each covalent bond must be broken - requiring a lot of energy!
- Poor electrical conductivity in diamond because there are no delocalised electrons because all electrons are used in forming covalent bonds.
- Graphite can conduct electricity though because there is an electron left over from forming the bonds which becomes delocalised.
- Graphite is weaker than diamond because it is made of layers which are easy to break because it only has vdw forces between layers. Diamond is strong because it is a tetrahedral and all electrons are used in the forming of covalent bonds.
- High melting and boiling points because of the strong electrostatic forces between oppositely charged ions.
- Ionic crystals conduct electricity when molten or in solution because then the ions can move around and therefore carry current.
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