5
$\begingroup$

In several pictures that I have seen of buckminsterfullerene and graphite (such as below), each carbon is bonded to only 3 other carbons, so it only forms 3 covalent bonds. enter image description here enter image description here

I asked my teacher about this and he says that each carbon only make 3 bonds and has a lone pair. These lone pairs are de-localised hence, that is why buckminsterfullerene is able to conduct electricity.

However, I am doubtful about this as how can a lone pair on an atom be de-localised. Would the electrons be in their orbitals, and not be able to freely move around the compound. I try searching the internet for any information, but there is no mention on how many bonds each carbon atoms makes.

I am guessing that there is alternating double bonds between each carbon so that each carbon has 4 bonds. It is these pi bonds which along the compound that makes it a hyper-conjugated compound. This would explain why buckminsterfullerene and graphite are able to conduct electricity. Am I correct?

$\endgroup$
8
$\begingroup$

Have you ever seen a picture of graphite, to begin with? It shares the same feature, i.e., that each carbon is bonded to exactly 3 other carbons. You may call it "alternating double bonds", but this is not quite correct either, because in fact all bonds are equal. Think of it as a resonance structure, much like benzene. This is the reason for graphite conductivity, too.

The idea about that lone pair is plain wrong. Carbon has but 4 valence electrons; once 3 of them are spent for sigma bonds, how could it have a lone pair?

Pure buckminsterfullerene does not conduct electricity (strictly speaking, it is a semiconductor, not a conductor like any metal). Some of its derivatives do, but that's another story.

$\endgroup$
  • 1
    $\begingroup$ Thanks. So, if graphite and buckminsterfullerene both have the same structure, why is only graphite able to conduct electricity, but not buckminsterfullerene? $\endgroup$ – Nanoputian Sep 14 '15 at 7:46
  • 3
    $\begingroup$ Because they don't have the same structure. Look again at that picture of graphite. Look at them layers, they are infinite. It's a huge system of conjugated pi bonds, from one end to another. That's what conducts electricity. With fullerene, it's just a system of such bonds within one molecule. Supposedly it could conduct electricity from one side of molecule to another, but that's about it. $\endgroup$ – Ivan Neretin Sep 14 '15 at 7:55
  • $\begingroup$ Fun fact: Graphite (at least an ideally layered) is only a conductor in two dimensions. $\endgroup$ – Martin - マーチン Sep 14 '15 at 12:36
  • $\begingroup$ Yes, of course. And nanotubes (at least some of them) are 1D conductors. $\endgroup$ – Ivan Neretin Sep 14 '15 at 13:44
  • $\begingroup$ Fun fact: Calculations gave me alternating single and double bonds along the six-membered rings and the five-membered rings of fullerene were exclusively single-bonds. $\endgroup$ – Jan Sep 19 '15 at 17:40

protected by Community Sep 27 '16 at 9:55

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.