Sulfer Dioxide resonance

[rmm30]

This question has been nagging me for a month and I'm hoping someone can clear it up. Fairly simple. Why does SO2 have 2 resonance structures? I thought that the preferable Lewis structure has the least amount of formal charges and lowest magnitude of formal charges. By that logic SO2
should look like:


O==S==O and not O--S==O (Charges and lone pairs not shown)

what gives?

---

Members don't see this ad.

 

[radmazindds]

Where have you seen it written that way? I'm pretty sure it's O=S=O
Perhaps you're referring to sulfuric acid (H2SO4)--in which (after it's been deprotonated), you could have resonance structures analogous to the ones you've posted.

EDIT: while O=S=O is the main (wc?) structure, additional resonance structures can ALSO exist. But you would have formal charges on the O and S. They would just contribute less to the structure because they aren't as stable.

[ O==S==O <-> -O--S+==O <-> O==S+--O- ]

This question has been nagging me for a month and I'm hoping someone can clear it up. Fairly simple. Why does SO2 have 2 resonance structures? I thought that the preferable Lewis structure has the least amount of formal charges and lowest magnitude of formal charges. By that logic SO2
should look like:


O==S==O and not O--S==O (Charges and lone pairs not shown)

what gives?

 

[rmm30]

Where have you seen it written that way? I'm pretty sure it's O=S=O
Perhaps you're referring to sulfuric acid (H2SO4)--in which (after it's been deprotonated), you could have resonance structures analogous to the ones you've posted.

EDIT: while O=S=O is the main (wc?) structure, additional resonance structures can ALSO exist. But you would have formal charges on the O and S. They would just contribute less to the structure because they aren't as stable.

[ O==S==O <-> -O--S+==O <-> O==S+--O- ]

Chads videos is where I saw it first. Then my chem text. Then google imaged "SO2 lewis". Chad never mentioned the structure with no formal charges. I'm pretty sure the 2 major res contributors have formal charges and I'd like to know why.

Furthermore the actual structure is more like
_ _ _ _ _ _
O_____S____ O where the pi electrons are delocalized between the 2 Oxygens

 

[radmazindds]

OHHHHHHHHHH! I think I see why!

Sulfur is right under Oxygen on the periodic table. It has six valence electrons just like oxygen. Look up ozone on wikipedia. Look at that structure. Look familiar? It has to do with hybridization/bonding. Though i can't tell you for sure. I'm guessing at this point.

Sorry for giving you wrong information earlier (that was embarassing...) but I googled Sulfur dioxide and saw O=S=O.... hmmmmm

http://en.wikipedia.org/wiki/File:Sulfur-dioxide-resonance-2D.png (from wikipedia)

Chads videos is where I saw it first. Then my chem text. Then google imaged "SO2 lewis". Chad never mentioned the structure with no formal charges. I'm pretty sure the 2 major res contributors have formal charges and I'd like to know why.

Furthermore the actual structure is more like
_ _ _ _ _ _
O_____S____ O where the pi electrons are delocalized between the 2 Oxygens

 

[rmm30]

OHHHHHHHHHH! I think I see why!

Sulfur is right under Oxygen on the periodic table. It has six valence electrons just like oxygen. Look up ozone on wikipedia. Look at that structure. Look familiar? It has to do with hybridization/bonding. Though i can't tell you for sure. I'm guessing at this point.

Sorry for giving you wrong information earlier (that was embarassing...) but I googled Sulfur dioxide and saw O=S=O.... hmmmmm

http://en.wikipedia.org/wiki/File:Sulfur-dioxide-resonance-2D.png (from wikipedia)

Cool thanks. If it's good enough for wiki it's good enough for me. In wiki I trust.