bond type for Resonance structure

[Nan_Guan_1L]

I'm confused about how to characterize the bond types and count the # of bonds for a resonance structure. for example, how many pai bonds does the resonance for SO2 have? This resonance contains two possibilities and each has 1 pai bond. how do we characterize the bonds in the resonance as a whole in this case? Thank you!

[Eve Gross-Sable 1B]

Hi! So SO2 has 3 possible structures, one has 2 double bonds (one between Sulfur and each oxygen) and the other two have a double bond between sulfur and one oxygen and a single bond between sulfur and the other oxygen. Since the second two structures are essentially mirrors of each other they have the same bond types, which would be two sigma and one pi. The other structure has two sigma bonds and two pi bonds. I don't think that you will be asked to combine this all into one because the structure with two double bonds is clearly the most stable while the other two have formal charges and will behave differently than the stable one. My guess is you would be asked to characterize the bonds in the stable configuration vs the unstable ones. Hope this helps!