Hybridization of Orbitals

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The simple answer is, “No”.

Chemists have proposed an explanation – they call it Hybridization.

Hybridization is the combining of two or more orbitals of nearly equal energy within the same atom into orbitals of equal energy.

Measurements show that

all four bonds in methane

are equal. Thus, we need

a new explanation for the

bonding in methane.

Slide 11

In the case of methane, they call the hybridization

sp3, meaning that an s orbital is combined with three

p orbitals to create four equal hybrid orbitals.

These new orbitals have slightly MORE energy than

the 2s orbital…

… and slightly LESS energy than the 2p orbitals.

1s

2sp3

2sp3

2sp3

2sp3

Slide 12

Hybrid Orbitals

Here is another way to look at the sp3 hybridization

and energy profile…

sp3

Slide 13

While sp3 is the hybridization observed in methane,

there are other types of hybridization that atoms

undergo.

These include sp hybridization, in which one s

orbital combines with a single p orbital.

This produces two hybrid orbitals, while leaving two normal p orbitals

sp Hybrid Orbitals

Slide 14

Another hybrid is the sp2, which combines two orbitals from a p sublevel with one orbital from an s sublevel.

One p orbital remains unchanged.

sp2 Hybrid Orbitals

Slide 15

Exclusion Warning

An understanding of the derivation and depiction of these orbitals is beyond the scope of this course and the AP Exam. Current evidence suggests that hybridization involving d orbitals does not exist, and there is controversy about the need to teach any hybridization. Until there is agreement in the chemistry community, we will continue to include sp, sp2, and sp3 hybridization in the current course.

Slide 16

Hybridization Involving “d” Orbitals

Beginning with elements in the third row, “d” orbitals may also hybridize

dsp3 = five hybrid orbitals of equal energy

d 2sp3 = six hybrid orbitals of equal energy

Slide 17

Hybridization and Molecular Geometry

A = central atom

X = atoms bonded to A

E = nonbonding electron pairs on A

Slide 18

Sigma and Pi Bonds

Sigma () bonds exist in the region directly between two bonded atoms.