Why giant ionic substance conduct electricity and why giant substances (except graphite) do not?
Giant ionic substance can conduct electricity only in aqueous state or in molten state. In solid state, it cannot conduct electricity because the ions are not mobile. Giant metallic substance can conduct electricity either in solid or in molten states. This is so because it has delocalised electrons that can act as charge carrier. Giant covalent compounds cannot conduct electricity neither in solid nor molten states. Although graphite is a covalently bonded, it has one delocalised electron per carbon atom.( sp2 hybridised orbitals). Hence it can conduct electricity.
