# Determining hybridization in a compound

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1. Jun 24, 2015

### fireflies

I've got several following questions on hybridization?

1) How many kinds of hybridization are there? Like sp, sp2,
Is sp2d is possible? Give examples.

2) How can we determine what kind of hybridization exist in atoms of a compound? I know several techniques but those seem like shortcut technique to me. I am not sure if they are true for any compound. Is there any absolute/general rule?

2. Jun 24, 2015

### Staff: Mentor

Have you tried googling for "sp2d hybridization"?

3. Jun 24, 2015

### fireflies

Until now, no.. I just searched in books.

Just now I googled. Same result as book. Here, given sp2d hybridization, even its orbital pic, but not finding any examples. (Other than a guy askin' for reasons of sp2d in copper tetra amine, if this surely is? Nd only 1 example? If it is due to this hybridization is very rare or generally not happens at all singly an exception?)

And I must've mentioned. I am not talking about (n-1)dnsnp2, rather talking about nsnp2(n+1)d. Another webpage, gave an unclear mention and example, maybe it mixed up both he hybridization

4. Jun 24, 2015

### Staff: Mentor

Took me less than a minute to find examples using google. You know, google shows more than one result, and "sp2d hybridization" are not the only keywords you can use. Just try harder.

5. Jun 24, 2015

### fireflies

And what about the second question? I know two rules-

1. Draw the molecular structure and calculate the lone pair+bonds (not a good rule of course as its not possible to knoe the structure of all compounds)

2) {valence electron of central atom-(charge of the compound) + no. of monovalent atoms}/2
But I am not sure is it true for all compounds

6. Jun 24, 2015

### fireflies

Not (n-1)dnsnp2, not even (n-1)p2(n-1)dns,

SPECIFIED
nsnp2(n+1)d
Where you've skipped one p-orbital to make the hybridization.

Are you really sure? I haven't found it yet. Not even copper tetra amine is its example as copper electronic configuration won't allow to.

But still trying to search it

7. Jun 25, 2015

### DrDu

1) There is a continuum of possible hybridizations between the ones you mentioned. E.g. if you have an s and a p orbital, if you mix them equally you get two sp hybrids, but you can also form an s orbital with just a little of p admixture and a p orbital with just a little of s admixture.
2) Hybridization does not "exist". I is a model to describe the bonding in molecules and in most of the cases models with different or no hybridization give similar results.
Hybridization is useful to get an explanation e.g. for the bonding in methane, which would be more difficult to explain using un-hybridized orbitals.
There are two conditions for hybridization to be useful: a) the atomic orbitals forming the hybrid should be of similar energy.
b) The two orbitals should be of approximately the same size.

a) rules out the use of hybrids in molecules like H2O or HF, because in O and F, the energetic difference between s and p is very large. It also rules out the use of d-orbitals in main group compounds.
b) This rules out the use of s and p hybridization in higher main group compounds as those of Si or P.

8. Jun 25, 2015

### fireflies

That makes sense to me..

But yet any example found where bond is explained by nsnp2nd?

(I'm sorry as I wrote previously (n+1)d, but cannot edit)

9. Jun 25, 2015

### fireflies

And what is the basic difference when there is equal portion of s and p, or more s less p or vice versa? All the three are the same sp, right?

10. Jun 25, 2015

### DrDu

In terms of the wavefunctions $\psi_s$ and $\psi_p$, the wave functions of the two sp hybrids are $\psi^{(1)}_{sp}=\frac{1}{\sqrt{2}}(\psi_s+\psi_p)$ and $\psi^{(2)}_{sp}=\frac{1}{\sqrt{2}}(-\psi_s+\psi_p)$. But this is only a limit of the continuum $\psi^{(1)}=\frac{1}{\sqrt{1+a^2}}(\psi_s+a\psi_p)$ and $\psi^{(2)}=\frac{1}{\sqrt{1+a^2}}(-a\psi_s+\psi_p)$, where a=0 corresponds to no hybridization and a=1 to the choice of sp hybrids. In a linear molecule A-B-C, the optimal hybridization for atom B will correspond to a value 0<a<1, in general.

11. Jun 25, 2015

### fireflies

Actually I just completed high school, not yet familiar with wave function as it is out of my syllabus. I think I must learn more to get the point you wrote in answer to my question.

12. Jun 25, 2015

### fireflies

At last I found out the answer of my thread in a book. Copper tetra amine is sp2d actually.

Why it is not dsp2 but sp2d in real is also explained, but not uploading as the book is not in english.

13. Jun 26, 2015

### DrDu

Cisplatin is also a nice example as it is of tremendous value in chemotherapy.