Sulphur Dioxide (SO2) Geometry & Hybridization

[gemma786]

Hi
I was trying to understand the geometry of Sulphur Dioxide molecule on the basis of hybridisation involved in the central atom. I found that Sulphur atom should have SP2 hybridisation. I want to know that is there any promotion of electron from 3 p-orbitals to 3d-orbitals and then forming dπ-pπ bonding?
Electronic Configration of Sulphur is [Ne]3s2 3p4 ,right ? It means in ground state it would have one fully filled 3p-orbital and two half filled 3p-orbitals. And if it hybridise as such including one s and two half filled p-orbitals leading to three sp3 hybrid orbitals one of which is fully filled and two half filled hybrid orbitals form sigma bond with two oxygen atom then this will lead to completion of octet for sulphur atom but not the octet to oxygen atom , isn’t it? Then how it is possible that it undergoes hybridisation with the promotion of promotion of electrons into 3d-orbitals ? Or SO2 has conformation something like ozone which textbooks promotes us to think about ? If SO2 has structure like the ozone inspite of sulphur atom have accessibility to d-orbitals then why is it so ?

 

[DrDu]

In general, in main group elements, d-orbitals aren't accessible for bond formation. Some 50 years ago people believed that d-orbitals are important in sulfur compounds but this has long been disproven.

 

[gemma786]

Drdu_.Thanks, for posting such a incomplete answer!
I have posted this thread so that I can come across people who really know the truth and don't hesitate to share that with other.
But anyways, thanks for replying.

 

[granpa]

is SO2 anything like NO2?

https://www.physicsforums.com/showthread.php?t=261728

 

[DrDu]

gemma786 wrote:
"Drdu_.Thanks, for posting such a incomplete answer!
I have posted this thread so that I can come across people who really know the truth and don't hesitate to share that with other.
But anyways, thanks for replying. "

You are welcome! But please take in mind that writing a satisfactory answer is not easy. First I don't know exactly your level and second I myself remember only vaguely the details, let alone some sound reference.
Anyhow, here is one:
http://dx.doi.org/10.1016/S1380-7323(99)80022-3

 

[gemma786]

Drdu_Once again Thanks.
The link provided by you helped me to understand what you wanted me to infer earlier.
Now I am putting up some thought about which I am not completely sure.
Formation of sulphut dioxide is a bimolecular process invoving one sulphur atom and one oxygen gas molecule when we
are producing SO2 by the combustion of sulphur in air.As the reacting molecules get closer to each other orbitals energy
started to spread out or disperse and then upper limit of energy level of s-orbitals stated to overlap lower energy level of p-orbitals
thus initiation the process of energy re-distribution between orbitals. As the reacting species come in close proximity their
hybrid orbitals started to overlap and arrange themselves in space. Afer the completion of reaction we get the product SO2
molecules whoes constituent species have undergone dynamic valance electron interaction without actual promotion of electron from
orbital to another,
As I said i am not sure about this.
I need help!

 

[DrDu]

First I have to say that I am not sure about the mechanism involved. I would guess that the first species that forms is SO and SO_2 forms only in a second step, but that's only a guess.
Second, there are two ways of thinking about bond formation and bond breakting. Thinking in terms of hybrid orbitals you are considering the valence bond approach. In that approach, it is not so much the orbitals that are changing but the weights of different pairing possibilities for the electronic spins.
The second approach would be molecular orbital theory. There bond formation depends mainly on the energies and overlapps of the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO, respectively) of the reactands. That's the frontier orbital theory of Fukui.

On the second approach there should exist tons of pedagogical expositions. For the first approach there are much less. There exist some pedagogical articles by Sason Shaik, who has apparently also published a book:
A Chemist's Guide to Valence Bond Theory
Sason S. Shaik, Philippe C. Hiberty - 2007

 

[gemma786]

Thanks Drdu.
But I think, I will have to work out mechanism myself.

 

[khadijha.ji]

can you tell that as sulfer has 3s2,3p4 electronic configuration than how its four electrons hybridized to form two sigma bonds two pi bonds and remain there one electron pair ,as 1s and 2 p electrons hybridized with oxygen atom to form two sigma bonds ,three remaining electron in p orbital are there,one electron make one pi bond with oxygen and one electron pair will remain as lone pair on sulfer atom there, so how second pi bond will form?

 

[DrDu]

First, it is not the electrons that are hybridized but the orbitals.
It is not possible to describe the bonding in S02 in terms of two pi bonds. Rather there is a resonance between a covalent pi bond between S and the first O and an ionic bond between S and the second O with an electron transferred from S to O. The two structures in resonance differ in which of the two O atoms is involved in the covalent and which in the ionic bond.

 

[khadijha.ji]

can you draw the molecular hybridization diagram of so2?if yes so please i need it you can snd it in my id that is khadijha.ji@yahoo.com please its a request...

 

[DrDu]

I can't paint on my pc. But it's not a problem of hybridization. you can assume that there are 6 electrons at oxygen 1, 7 at oxygen 2(which therefore has a negative formal charge), and 5 at sulfu(which has a positive formal charge)r. From the 5 electrons, 2 are in the s orbital of S, and one is in each of the 3 p orbitals.

 

[khadijha.ji]

thanks for enough help.are u a chemistry teacher? if you don't mind than can you tell me about your qualification?and can i ask you some other sorts of questions related to chemistry subject?

 

[khadijha.ji]

have you command on vsepr structers?

 

[DrDu]

No, I am not a teacher, but I have got a diploma in chemistry and alos worked during my thesis on theoretical chemisty.

 

[khadijha.ji]

diploma?from which country do you relate?can u recommend me the specialization in chemistry best for girls and also have scope from organic, inorganic, physical, analytical and biochemistry?which one is best for me?i am a chemistry subject student.

 

[DrDu]

diploma?from which country do you relate?can u recommend me the specialization in chemistry best for girls and also have scope from organic, inorganic, physical, analytical and biochemistry?which one is best for me?i am a chemistry subject student.

Germany, but since I got my diploma it has switched to the Bachelor/Master type of degrees.
It's quite some time since I am out of chemistry, so I cannot give you too actual advices.
But I would recommend you to just follow your interest taking in mind where you will probably end up with a given specialization and whether you want to pursue this all your career. I would also not differentiate between girls or boys, lest you are pregnant and can't do lab work ( I know one girl who did her thesis in theoretical chemistry for that reason).

 

[khadijha.ji]

can u tell that solvent effect the product in sn2 reaction as it effect the sn1 reactions where it help in generation of carbocation?although i know that a polar solvent like water can act as nucleophile but if in sni type of reaction solvent which can't act as nucleophile as their is nucleophile present than how it effect the reaction?

 

[DrDu]

a) I don't understand your question. Maybe you can reformulate it.
b) Maybe you could start a new thread as it is unrelated to SO2.

 

[khadijha.ji]

i asked a question related to nucleophilic substitution reaction do you know about this topic?yup this is not related to so2.i am new here i have no idea how to ask question there i found this page when i was searching for so2 structure but now i got that's answer.now i have to ask the question in which i got confusion from the members of this forum who are able to answer them and i think you are one of them can you tell me answer live i mean when we both are online?

 

[DrDu]

When you go to the "chemistry" sub-forum, there is a button called "New topic". There you can start a new thread.
I know about SN2 and SN1 reactions, but I have problems to understand what you were writing and what exactly your question is.