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I have the following molecule. enter image description here

And I have to determine the decreasing order of bond order of $\ce{C_1-C_2,C_3-C_6,C_2-C_3}$

I know that I have to take into consideration the various resonating structures but can't get the final answer. In my view, $\ce{C_1-C_2}$ should have the highest bond order because of hindrance by $\ce{C_3-C_6}$. I have this resonating structures.the second one has least contribution because of separation of positive and negative charges.so we could perhaps ignore it.in the other two each time either carbon has double bonds which should imply same bond order. enter image description here Please help me with a proper reasoning.

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  • $\begingroup$ Start by actually drawing all of the resonance structures. What do you see that relates to your question? $\endgroup$ – ron Dec 15 '16 at 18:40
  • $\begingroup$ @ron please check the edit of the question. $\endgroup$ – Pink Dec 15 '16 at 20:20
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    $\begingroup$ @aniline what you drew is not a resonance structure. (Also, can you find a better camera? Your pictures are awfully hard to see.) $\endgroup$ – Jan Dec 15 '16 at 20:21
  • $\begingroup$ @Jan sorry for the pic (I would try to get a better camera.) However what would be the correct then if that posted are not? $\endgroup$ – Pink Dec 15 '16 at 20:29
  • $\begingroup$ @aniline A resonance structure should not add new bonds like you did between carbons 1 and 5. (You might as well just use Paint or something …) $\endgroup$ – Jan Dec 15 '16 at 20:35
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While drawing resonance structures, the sigma bond skeleton in each structure should remain same. Here you have changed the skeleton. Keep the skeleton unchanged and just move or "delocalize" the pi-electrons and while doing so also keep in mind the valencies of atoms.

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