Graphene (/ˈɡræfiːn/) is an allotrope of carbon in the form of a single layer of atoms in a two-dimensional hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes, including graphite, charcoal, carbon nanotubes and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the ultimate case of the family of flat polycyclic aromatic hydrocarbons. Graphene has a special set of properties which set it apart from other allotropes of carbon. In proportion to its thickness, it is about 100 times stronger than the strongest steel. Yet its density is dramatically lower than any steel, with a surfacic mass of 0.763 mg per square meter. It conducts heat and electricity very efficiently and is nearly transparent. Graphene also shows a large and nonlinear diamagnetism, even greater than graphite, and can be levitated by Nd-Fe-B magnets. Researchers have identified the bipolar transistor effect, ballistic transport of charges and large quantum oscillations in the material.Scientists have theorized about graphene for decades. It has likely been unknowingly produced...