All possible resonance structures for SO4 2-

[Faelyn]

Homework Statement

What are all of the possible Lewis Dot diagrams for SO4 2-?

Relevant Equations

n/a

So I know about the 6 stable resonance Lewis Dot diagrams for sulfate:

As well as the unstable diagram that only has single bonds between the sulfur and oxygen atoms.But, is it possible for there to be other resonant structures with either 1 or 3 double bonds, even if they're more unstable? I was thinking the one with a single double bond should be possible, but not as much for the three double bonds due to sulfur only having enough valence electrons for six bonds. In both cases the charge is 2- and there are 32 electrons.

(sulfur is double bonded to only 1 of the oxygen atoms, seems totally possible)

(sulfur is double bonded to 3 of the oxygen atoms, doesn't seem that possible)

 

[Mayhem]

Unless it breaks the laws of physics, if you can draw it (following the rules of resonance structures), it in principle exists. However, its contribution to the resonance hybrid could be so negigible that it's meaningless.

 

[Faelyn]

Unless it breaks the laws of physics, if you can draw it (following the rules of resonance structures), it in principle exists. However, its contribution to the resonance hybrid could be so negigible that it's meaningless.

So could it even be possible with 4 double bonds, or with one of the oxygen atoms triple bonded?

 

[Mayhem]

So could it even be possible with 4 double bonds, or with one of the oxygen atoms triple bonded?

Maximum Valence of sulfur is 6, so octovalence is probably not possible.

 

[dextercioby]

Shouldn't you be guided by the octet rule still? How many electrons would be available to the Sulfur atom?

 

[Faelyn]

Shouldn't you be guided by the octet rule still? How many electrons would be available to the Sulfur atom?

Well sulfur can form 6 bonds maximum due to having access to the D orbital, which is why I'm thinking the scenario with only one double bond should be possible while the one with three double bonds wouldn't be possible.

But then theoretically a scenario with one triple bond and 3 single bonds might also be possible since there's still 6 bonds in total.

 

[mjc123]

You've got an SO₄^3- among your 6 "stable" structures!

 

[DrDu]

Well sulfur can form 6 bonds maximum due to having access to the D orbital,

The availability of d-orbitals in main group elements for bonding has been disproven more than 50 years ago.
This is a nice modern reading on the subject: https://doi.org/10.3390/chemistry4040082

 

[docnet]

you are missing one 'resonance structure' with two S=O bonds.

 

[docnet]

and the one on the top right with one S=O bond isn't stable