[mcfaker123]

Hello,

I have seen 2 kind of "lewis notations" for molecules, I will give an example:


Is there anyone on this forum who is well familiar with the second notation? I Dont see any formal charge next to the S and other 2 O's, does that mean that the formal charges of S and the 2 O's are zero?

Now if that is true im very confused then, because the first notation has 2+ as formal charge for S!! How is that possible? Im really confused here, could someone please help me out?

Thanks in advance!!

[magician4]

Is there anyone on this forum who is well familiar with the second notation? I Dont see any formal charge next to the S and other 2 O's, does that mean that the formal charges of S and the 2 O's are zero?

yes

(...)Im really confused here(...)

your confusion is justyfied

fact of the matter is, that there's simply is no good way to describe the sulfate- dianion ( or, for that mater: SiO₄^4-, PO₄^3- , ClO₄^- : all the same problem) in a Lewis-structure type of fashion, as you'll always run into one kind of violation or absurdity or another.

only when you come to MO theory or , even better "modern bonds" like 3c4e , things will become clearer ( and are getting confused again, when still later you advance to ultimative molecule analysis by ab initio QM calculation)

regards

Ingo

[mcfaker123]

Thank you for your answer, my teacher says the opposite, he says that S has a 2+ formal charge and all O's have a formal charge of -1 for this structure!:



This structure is used in our book. My teacher says " that the book didnt put the formal charges for S and the other 2 O's " I dont know what he means by that whether he means they actually forgot to mention it or not, but I think he is making a mistake himself & the book is correct so the book did not forget to put the formal charges, because they are zero.

Could this be the case here maybe? Maybe my teacher is confused himself and he doesnt even know it?

Thanks in advance!

[magician4]

Thank you for your answer, my teacher says the opposite, he says that S has a 2+ formal charge and all O's have a formal charge of -1 for this structure!:

for the structure shown, clearly there is no such thing as a formal charge at the sulfur, and there are only two oxygens charged, the other two uncharged shown

asides from that:
"formal charge", yeah! deus ex machina!
nobody knows what the heck a "formal charge" is, except of another word for " I don't know the answer myself, I don't understand it either, but I've got a nice word for it"
  sounds good , explains nothing

and hence, i would agree that this possibly might be true:

Maybe my teacher is confused himself and he doesn't even know it?

regards

Ingo

[mcfaker123]

Yes thank you for the answer I appreciate it. He definitely told us that the book didnt mention the formal charges, & he told that S had a formal charge of +2 and the other 2 O's also had a charge of -1. 

I dont think the book is incorrect, I think he is making a mistake himself, I will address that to him & tell the results

[AWK]

There are other possibilities
http://en.wikipedia.org/wiki/Sulfate