In graphene, each carbon atom is sp 2 -hybridized, meaning three of its four valence electrons form σ-bonds with adjacent atoms, creating a planar structure. The remaining p-orbital electron from each carbon atom forms a delocalized π-bonding network, which extends over the entire sheet. This delocalized π-electron system is responsible for graphene's exceptional electrical conductivity, allowing electrons to move freely across the lattice with minimal resistance .