[anrea92]

Well, sulphur in SF6 for istance has got a sp3d2 hybridization and I can see why, it has got the principal quantum numer n=3 and therefore it has got the possibility to
occupy atomic orbitals of "d" kind and it finally has got (after the hybridization) 6 unpaired elctrons.
But why in H2SO4 sulphur has got a sp3 hybridization? How is it possible? I see, the structure is tetrahedral but, if it has got a sp3 hybridization, the hybridized orbitals are s (1) and p (3) and consequently the structure should be with two lone pairs and two unpaired electrons. On the contrary there are, in the H2SO4 structure, 6 unpaired electrons (which should be obtained from the sp3d2 hybridization).
Conclusion: why in H2SO4 the hybridization is sp3 and not sp3d2?
How can the sp3 hybridization (which should involve just 1 "s" orbital and 3 "p" orbitals gives rise to 6 unpaired electrons?

p.s = it's all the same for SO3, isn't it? But there why is the hybridization sp2 and not sp3d2 again?

I'm sorry, I know it will be surely easy for you but I've been looking for the answer everywhere, but I really can't understand.
Thanks to all who will try to help me out.

[stevet]

Why do you say that the sulfur in the H₂SO₄ has sp³ hybridization?

[anrea92]

It's not me to say that, it's my book!
Isn't the hybridization of that kind? Is it sp3d2 as I thought?

[stevet]

From what i can see you are right. There is no way that the three sp3 orbitals can accomodate the 12 electrons. You have to have 6 orbitals as you say.
It seems like your book is associateing the tetrahedral geometry with a specific hybridization i.e. that tethrahedral geometry = sp3, however this is not the actual case, as illustrated by your example.

[anrea92]

I mean: if I follow the structure of H2SO4, I'm disposed to believe that it has got a sp3 hybridization since its structure is tetrahedral and only sp3 hybridization has got tetrahedral structure; but if I follow the electrons, there cannot be 6 unpaired electrons with sp3 hybridization and I'm disposed to believe that the hybridization is a sp3d2 one.
Which way should I choose to get the right answer (which would be: the hybridization is sp3 or sp3d2? And why?) since both of the possibilities lead me to different answers?