Thread: Sulfur dioxide structure, bonds

Hi I am pretty confused about the structure of sulfur dioxide, recently I had an argument with my chemistry teacher about the structure of sulfur dioxide. She insisted that the bonds between Sulphur and oxides are single bonds (her argument was, that sulphur can't have four bonds), while I think the bonds are double (as stated in 3/4 books I have reviewed afterwards (and also on wikipedia)). Also, if there wasn't double bond in sulfur dioxide, how could it be in the Sulfurous acid, where I clearly don't see any other alternatives of bonding. (Unfortunately, it didn't came to my mind at the lesson) In one older book (1960), I've read that the bonds are single, but showing the properties of double bonds. Newer literature said the bonds were double, however they differed in the principle of formation. One stated the formation of double bond is due to the pd2 hybridization of valence shell orbitals, the others (including wiki) that one bond is double and the other one dative and that the d orbitals are not concerned. However, if the bond was dative, the O atom would have to have empty p orbital, which would be violation of Hund's principle... how is this possible? so.. are the bonds in sulfur dioxide double or single, and what's the mechanism of it's formation? thanks for the answers and your time, rickettsie

Thanks very much, the molecular orbital theory is much more fun than what we're taught in school, I've read about it, but never really used it. I'll have to investigate it more deeply. Thanks again