Structure of SO2

[FeralisExtremum]

I was going through Chad's video on Lewis Structures and once of his examples was sulfur dioxide (SO2). What's the deal with the structure here? He uses the resonance structures:

But, these resonance structures have formal charges, which are not ideal. If we use the expanded octet that S has available, this structure seems ideal as it eliminates any formal charge:

Wikipedia's explanation for the discrepancy is: "Computational chemistry (using Natural bond orbitals) has found that the common expanded d-orbital model for SO2 is not a very stabilizing interaction and therefore not an important contributor to bonding in SO2. In other words, the 3d orbitals of sulfur are too high in energy to be much use"

But how was I supposed to be aware of that exception when figuring out which Lewis structure(s) are correct? Is this just one of those things you're supposed to know, or is there a method to being able to determine when to use expanded octet?

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[Dotoday]

So2 is Bent. It has 2 atrachments ( double bonded O's) and a lone pair. That is a correct structure. It has sp2 hybridization and a loan pair. This gives it a bent shape. Hope it helps. Good luck.

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[dentalstudent2021]

anyone care to expand on this. This threw me off as well. I still don't comprehend this exception. I too thought the structure would be what feralis shows here instead of the one with resonance.

 

[gabtse]

1. The total number of valence electrons in the molecule is 18:

6 (from the S atom)
12 (from the two O atoms)

2. No. of electrons for individual atoms is 8(3) = 24.

No. of bonds allowed = (24 - 18)/2 = 3

It will have to be the resonance structure with the three bonds involved.

Use your textbook for complete references and understanding when in doubt. All other resources have their limitations.

 

[O Gaúcho]

Dang studying for the DAT for three years seems brutal

 

[pikachurro]

And he still got a 14AA smh


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[FeralisExtremum]

Dang studying for the DAT for three years seems brutal

I think it would be impossible, I had a few false starts like this one that never lasted more than a week...sad times.

And he still got a 14AA smh


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15 TS and a 16 in Ochem but you never mention that part do you???