Diamond

The hardest natural material. Each carbon atom bonded to four neighbors in a tetrahedral lattice.

sp3 hybridization

Graphite

Layered hexagonal sheets weakly bonded by van der Waals forces. Excellent electrical conductor along planes.

sp2 hybridization

Fullerene

Spherical C60 molecule. 20 hexagons and 12 pentagons forming a soccer-ball structure.

C60 Buckminsterfullerene
|

Nanotubes

Cylindrical carbon structures with extraordinary tensile strength. Single-wall and multi-wall variants.

~63 GPa tensile strength

Graphene

Single-atom-thick sheet of carbon. 200x stronger than steel. Extraordinary thermal and electrical conductivity.

10^8 S/m conductivity

Amorphous

Disordered carbon without crystalline structure. Found in soot, coal, and activated carbon filters.

No long-range order

Carbon Cycle

Biogeochemical cycle where carbon exchanges between atmosphere, oceans, soil, and living organisms.

~750 GtC atmosphere

CO2 Capture

Technologies for removing carbon dioxide from point sources or ambient air. Key to climate mitigation.

DAC: $300-600/tCO2

Carbon Dating

Radiocarbon dating using C-14 decay. Half-life of 5,730 years determines age of organic materials.

C-14 t1/2 = 5,730 yr