Graphite has a layered structure. Each carbon atom within a layer is bonded to three other carbon atoms in a hexagonal lattice. These three bonds are formed using sp² hybrid orbitals. The remaining unhybridized p-orbital on each carbon atom overlaps with adjacent p-orbitals, creating a delocalized pi electron system across the layer. sp³ hybridization occurs in diamond, where each carbon atom forms single bonds with four other carbon atoms in a tetrahedral structure.