Graphite is the non-metal that conducts electricity.

Graphite is a unique form of carbon that has a layered structure. This unique structure allows graphite to conduct electricity, making it an exception among non-metals.

Reasons why graphite can conduct electricity:
- **Layered structure:** Graphite consists of layers of carbon atoms arranged in a hexagonal lattice. These layers are free to slide over each other, allowing electrons to move freely throughout the material.
- **Delocalized electrons:** In the structure of graphite, each carbon atom is bonded to three other carbon atoms, leaving one electron free to move. These delocalized electrons are responsible for the material's ability to conduct electricity.
- **Weak intermolecular forces:** The weak Van der Waals forces between the layers of graphite allow for easy movement of electrons between the layers, further enhancing its conductivity.

Comparison with other non-metals:
- **Iodine:** Iodine is a non-metal that does not conduct electricity. It exists as diatomic molecules held together by covalent bonds, and its electrons are localized within the molecules, preventing the flow of electricity.
- **Coal:** Coal is also a non-metal that does not conduct electricity. It consists of carbon-containing compounds with localized electrons, similar to iodine, which do not allow for the conduction of electricity.
- **Diamond:** Diamond, another form of carbon, is a non-metal that does not conduct electricity. Its rigid, tetrahedral structure locks the electrons in place, preventing them from moving freely and conducting electricity.

In conclusion, graphite's unique structure and delocalized electrons enable it to conduct electricity, distinguishing it from other non-metals like iodine, coal, and diamond.