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How could you tell whether or not a molecule *could* have pi bonds?

  1. Dec 11, 2006 #1
    Just by looking at its Lewis structure, how could you tell whether or not a molecule could have pi bonds?

    Thanks in advance.
  2. jcsd
  3. Dec 11, 2006 #2
    This is probably an oversimplified answer, but...Single bonds are made up of 1 sigma bond. Double bonds are made up of 1 sigma and 1 pi bond. Triple bonds are made up of 1 sigma and 2 pi bonds. So if the lewis structure for a molecule has double or triple bonds, it will have pi bonds.
  4. Dec 11, 2006 #3
    Thanks for your reply Cesium, but how do I tell if a molecule has multiple bonds if I'm only given its Lewis structure? Is there a simple way to do so, or do I have to actually draw it out?
  5. Dec 11, 2006 #4
    Yes, you have to draw out the Lewis structure to see if the molecule has double/triple bonds.
  6. Dec 13, 2006 #5


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    Staff Emeritus
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    Gold Member

    I'm not sure I understand this question. If you've been given the Lewis structure (aka Lewis dot diagram), why would you want to draw it out again?

    In most cases, you could, as explained by Cesium. It is possible, however, to have pi bonds in a molecule with just a single-bond, but this is quite rare. When you get to molecular orbital theory, you will understand how this is possible.
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