Carbon and its allotropes

• Diamond - an extremely hard, transparent crystal, with the carbon atoms arranged in a tetrahedral lattice. A poor electrical conductor. An excellent thermal conductor.
• Graphite - a soft, black, flaky solid, a moderate electrical conductor. The C atoms are bonded in flat hexagonal lattices, which are then layered in sheets.
• Amorphous carbon
• Fullerenes, including "buckyballs", like C₆₀, and carbon nanotubes