Graphite conducts electricity due to delocalized electrons located within which part of its structure?

• A. Within the layers
• B. Between the layers
• C. In the carbon-oxide regions
• D. In the interstitial spaces

Answer: (A)

Graphite conducts electricity because delocalized electrons sit in the pi system of the planar carbon layers. In each layer, carbon forms three sigma bonds, using three valence electrons, leaving one electron in a p orbital that overlaps with neighboring p orbitals to create a delocalized cloud across the layer. These mobile electrons can move easily within a layer, allowing electrical current to flow. There is little electron mobility between layers because the layers are held together by weak van der Waals forces, so conduction across layers is poor. Graphite has no carbon-oxide regions, and the interlayer spaces are just gaps, not regions of delocalized electrons. So the delocalized electrons reside within the layers.