Why Can Graphite Conduct Electricity

Graphite can conduct electricity because of its unique atomic structure, which allows electrons to move freely across its layers. Unlike many non-metallic substances, graphite has delocalised electrons that are not bound to a single atom or bond. These electrons are free to move within the layers of carbon atoms, enabling graphite to carry an electric current.

Each carbon atom in graphite forms three covalent bonds with neighbouring carbon atoms in a hexagonal arrangement, leaving one electron from each atom unbonded. These unbonded electrons become delocalised, forming a 'sea' of free-moving electrons within each layer. It is this sea of electrons that allows electricity to flow when a voltage is applied.

Structure of Graphite and Electron Mobility

Graphite is made up of many layers of carbon atoms arranged in flat, two-dimensional sheets. These layers are held together by weak van der Waals forces, which allow them to slide over one another easily. Within each layer, however, the bonds between carbon atoms are very strong due to the covalent bonding.

The key to graphite’s conductivity lies within these layers. Because each carbon atom only forms three bonds, the fourth valence electron is left free. These spare electrons form a network of delocalised electrons within the layer, much like what occurs in metals. When a potential difference is applied across the graphite, these electrons can move and carry the charge, allowing electrical conduction.

Why Other Forms of Carbon Do Not Conduct

Other forms of carbon, such as diamond, do not conduct electricity because all four outer electrons of each carbon atom are involved in strong covalent bonds. In diamond, there are no delocalised electrons, so there is no mechanism for current to flow.

This contrast highlights how the arrangement of atoms directly affects a material’s electrical properties. Graphite’s layered structure and the presence of free electrons give it conductive properties, whereas diamond’s rigid, three-dimensional structure makes it an insulator.

Graphite in Practical Applications

Graphite’s ability to conduct electricity makes it valuable in a range of industries. It is used as a conductor in batteries, electrodes, and electric motor brushes. It also plays a role in certain types of sensors and is being explored as a component in advanced materials like graphene and flexible electronics.

Its unique combination of conductivity, heat resistance and lubricating properties makes graphite an important material in both traditional and high-tech applications. From arc welding to nuclear reactors and renewable energy technologies, graphite’s electrical behaviour continues to be essential.

Conclusion

Graphite can conduct electricity because of the delocalised electrons in its layered structure. These free electrons, which move easily between carbon atoms within each layer, allow an electric current to pass through the material. This distinctive property sets graphite apart from other non-metals and even other forms of carbon, making it one of the few naturally occurring electrical conductors outside of the metal category.