Graphite is the stable variety of carbon under standard conditions of temperature and pressure.The carbon atoms are arranged in parallel planes with a hexagonal network of atoms linked by sigma bonds involving sp2 hybrid orbitals and pi bonds involving the remaining p orbital,van der Waals attractions between the graphitic sheets provide the cohesion of the three-dimensional structure of graphite.Graphite exfoliation is a well-known process in carbon chemistry.An intercalation compound is first synthesized using reactants with strong redox properties.The intercalated graphite is then heated and the exfoliation occurs.A graphite vermicular powder is obtained.When recompressed,this powder gives carbon sheets such as Papyex or Flexigraf flexible graphites.These commercially available materials can be impregnated with an aluminum trichloride/diethylether solution whose oxidation by atmospheric oxygen,initiated by an open flame,reproduces the exfoliation phenomenon.This kind of reaction has been called pseudo-exfoliation of carbonaceous material.The demonstration discussed here and shown in the videos available in the Supplemental Materialspectacularly illustrates the layered nature of graphite (Figure 1).
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