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Graphite's delocalised electron?

  1. Dec 7, 2006 #1
    They say 3 of graphite's electrons are covalently bonded and the other one is delocalised. But it shares among the other carbon atoms as well as having it itself because no carbon atom is charged in graphite. But that means it is very much covalent in nature? Why not have a double bond somewhere to explain the extra delocalised electron in every carbon atom in graphite? Or is it the case that they want to say that this electron is not fixed so can double bond with any of the three neighbouring carbon atoms?

    Is that different to saying it forms a double bond since a double bond in reality means a reasonance structure where the bonding is not fixed anyway.
     
    Last edited: Dec 7, 2006
  2. jcsd
  3. Dec 20, 2006 #2
    Did you study Benzene? It's the same principle. To see the resonance as an alternating formation of single/double bonds is not exact. Actually the electrons forms an entire molecular bond, that is, it is effectively delocalized in all the molecule, that is, the electronic "cloud" is made of two doghnuts over the plane of the molecule, on opposite sides.

    In graphite, all the Benzene rings become one, in this sense: the electrons are delocalized in all the plane of the molecules, above and under.
    Many planes of molecules = many layers.
     
  4. Dec 26, 2006 #3

    Gokul43201

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    Because covalent bonds (including double bonds) are localized in nature.

    A double bond is not a resonance hybrid. It is, an approximation based on overlap of localized, independent atomic orbitals (typically, but not necessarily, one sigma overlap and one pi overlap).

    ("Independent" means that I can write the many-electron wavefunction as a product of many single-particle wavefunctions).
     
    Last edited: Dec 26, 2006
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