Explain that each carbon atom in graphite forms three covalent bonds.

In graphite, each carbon atom forms three covalent bonds with other carbon atoms, resulting in a planar structure of hexagonal rings. This bonding arrangement allows for the formation of layers that can slide over one another, giving graphite its lubricating properties. The fourth outer-shell electron from each carbon atom becomes delocalised, contributing to electrical conductivity. This unique bonding and structure differentiate graphite from other carbon allotropes, enabling its use in applications such as pencils and lubricants.