The original question in my test was whether all bonds in the aforementioned molecule are of same length. According to the solution booklet, it is not because pi electrons are not delocalised due to anti-aromatic character.

This seems a bit weird...

  • $\begingroup$ What's weird about it? Indeed, there is no aromaticity here, hence different bond length. $\endgroup$ – Ivan Neretin Feb 19 '19 at 7:56
  • $\begingroup$ It's weird because resonance takes place regardless of the aromatic or anti-aromatic character of a molecule. Hence shouldn't the bond order be 1.5 for every C-C bond?? $\endgroup$ – Shiladitya Mukherjee Feb 19 '19 at 7:59
  • $\begingroup$ If you look at them long enough, yes. If you take a flash photo (figuratively speaking), then yes for aromatic compounds, but no for antiaromatic, like this one. $\endgroup$ – Ivan Neretin Feb 19 '19 at 8:44
  • $\begingroup$ May find the answer here. $\endgroup$ – Mathew Mahindaratne Feb 20 '19 at 2:29