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Graphene (/ ˈ ɡ r æ f iː n /) [1] is a carbon allotrope consisting of a single layer of atoms arranged in a honeycomb planar nanostructure. [2] [3] The name "graphene" is derived from "graphite" and the suffix -ene, indicating the presence of double bonds within the carbon structure.
Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. [1]
A news release from the Harvard-Smithsonian Center for Astrophysics described the 2,500-mile (4,000 km)-wide stellar core as a diamond, [49] and it was named as Lucy, after the Beatles' song "Lucy in the Sky With Diamonds"; [50] however, it is more likely an exotic form of carbon. Penta-graphene is a predicted carbon allotrope that utilizes the ...
A highly exothermic reaction combusts magnesium in an oxidation–reduction reaction with carbon dioxide, producing a variety of carbon nanoparticles including graphene and fullerenes. The carbon dioxide reactant may be either solid (dry-ice) or gaseous. The products of this reaction are carbon and magnesium oxide. [107] [108]
Graphene is a semimetal whose conduction and valence bands meet at the Dirac points, which are six locations in momentum space, the vertices of its hexagonal Brillouin zone, divided into two non-equivalent sets of three points. The two sets are labeled K and K′. The sets give graphene a valley degeneracy of gv = 2.
Homonuclear triatomic molecules contain three of the same kind of atom. That molecule will be an allotrope of that element. Ozone, O 3 is an example of a triatomic molecule with all atoms the same. Triatomic hydrogen, H 3, is unstable and breaks up spontaneously. H 3 +, the trihydrogen cation is stable by itself and is symmetric.
Pure graphene and gold-decorated graphene were each successfully integrated with the substrate. [25] An aerogel made of graphene layers separated by carbon nanotubes was measured at 0.16 milligrams per cubic centimeter. A solution of graphene and carbon nanotubes in a mold is freeze dried to dehydrate the solution, leaving the aerogel.
It was studied in detail by Kohlschütter and Haenni in 1918, who described the properties of graphite oxide paper. [9] Its structure was determined from single-crystal diffraction in 1924. [10] The theory of graphene was first explored by P. R. Wallace in 1947 as a starting point for understanding the electronic properties of 3D graphite.