The arrangement of carbon atoms in graphite is considerably different from that in diamond. In graphite, each carbon atom is covalently bonded to three other carbon atoms. All the bond angles are 120°, which is what would be expected if only three bonding electron pairs surrounded the carbon atoms. However, a check on the number of electrons reveals that there is one electron per atom left over. These electrons are delocalized and explain the electrical conductivity of graphite. Although graphite is composed of giant molecules, its atoms are arranged in layers that can slide past one another. Weak van der Waals forces hold the layers together.
The internal structure of graphite accounts for its:
Graphite compoundsThese are compounds formed by penetration of reactants between the layers of graphite. Graphite oxide, approximately C2O (graphite plus HNO3 or KMnO4) and graphite fluoride (graphite plus F2) are non-conducting because of break-up of the aromatic systems of the sheets (graphite fluoride is an efficient lubricant, and is also used with lithium in batteries). In the conducting intercalation compounds various species are inserted between the sheets. The reactivity of the intercalated compound is profoundly modified, e.g., hydrolysis of fluorides is reduced.
Related category INORGANIC CHEMISTRY
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