Does tetrachlorodibenzo-p-dioxin (2,3,7,8) have a nonzero dipole moment?

I've looked at and drawn the structure, and I originally felt that it would be nonpolar - as I believe all the dipoles would cancel out, but I'm not 100% sure. I might be too dependent on the fact that it *looks* symmetric.


Also, is it true that the overall molecule shape would be planar? And is the hybridization of the oxygen atoms sp3 like I think they are?


**Edit**: Thanks to a commenter, I have changed the question to ask about the dipole moment in hopes of being more clear. I'd also like to add that this is a homework question that I am stuck on (for general chemistry l) and the teacher hasn't been the most thorough which is why I am here trying to teach myself.


[![enter image description here](https://i.stack.imgur.com/ILOtw.png)](https://i.stack.imgur.com/ILOtw.png)




The best answer for this seems to be in [Structure, Energy, Vibrational Frequencies, and Potential Energy Curve of
2,3,7,8-Tetrachlorinated Dibenzo-p-dioxin: Ab Initio MO Studies](https://pubs.acs.org/doi/abs/10.1021/jp952704e) *J. Phys. Chem.*, 1996, 100 (12), pp 4810–4814. 


This research finds that though planar is the lowest energy conformation, the energy for bending with respect to the O-O axis from 180 degrees to 170 degrees is only 0.008 kcal/mol. The molecule flaps like a butterfly. 


The article says: 



> 
> At ambient temperatures, nonplanar conformations
>  will be significantly populated for this potential. This prediction
>  accounts for the experimental results that the electric dipole
>  moment of the DD molecules is reported to be 0.64 D. [reference 24] 
> 
> 
> 


Where "DD" means the unsubstituted dioxin and where reference 24 is Higashi, K.; Uyeo, S. *J. Chem. Soc. Jpn.* 1941, 62, 396. 


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