Page 1 of 1

### SO2 Lewis Structure

Posted: Mon Nov 05, 2018 11:43 am
In class today Lavelle said that the structure was o=s=o, but shouldn't it actually be o-s=o, since it has a net FC of 0 and follows the octet rule?

### Re: SO2 Lewis Structure

Posted: Mon Nov 05, 2018 11:59 am
The formal charge for the one with a double bond and one single bond, the O on the right is the only one with a formal charge of 0. The one on the left has a formal charge of -1 and S has a fc of +1. When both bonds are double bonds the formal charge of all three change to 0 which mean that is the most likely lewis structure for SO2.

### Re: SO2 Lewis Structure

Posted: Mon Nov 05, 2018 1:20 pm
There should be double bonds from S to O since this gives us the lowest formal charges. Remember, S can have an expanded octet, so S would have have a double bond with each of the Os and one lone pair and each of the Os would have two lone pairs to fill their octets.

### Re: SO2 Lewis Structure

Posted: Mon Nov 05, 2018 1:31 pm
I spoke to Dr. Lavelle after class today as I had drawn resonance structures to answer this question. I drew O-S=O <-> O=S-O with a lone pair of electrons on S.

O=S=O is BETTER because this gives every atom a 0 formal charge and S can use it's d orbitals to hold extra electrons in bonding.

### Re: SO2 Lewis Structure

Posted: Mon Nov 05, 2018 2:16 pm
Sulfur is one of those elements in the 3rd row p-block that can form an expanded octet as it can use its d-orbitals to fit more electrons.The goal of a lewis structure for atoms that have an expanded octet is to ensure that all the formal charges of each atom is zero, especially the central atom. S=O=S with two lone pairs on each S and one lone pair on the O is the more stable structure for SO2 because all of the formal charges are zero. :)