s character in bond

This can be explained in form of hybridization. Study the following data
carefully.

For sp hybridization, s character is 50% while p character is also 50%
For sp2 hybridization, s character is 33% while p character is also 67%
For sp3 hybridization, s character is 25% while p character is also 75%

For both sp and sp2 hybridization, they have more s character comparing p
character. This implies, more electrons from s will be close(接近) to nucleus.
This is due to the penetrating effect, which indicates s orbital having a greater
chance to move towards the nucleus than that of p- and d- orbital!

In the light of a general principle, the closer the distance between the electron density (provided by s) and nucleus /nuclei, the stronger is the electron -
nuclei/nucleus attraction. And the stronger is the bond energy.

As benzene, each carbon is sp2 hybridized. This signifies each of them has a
higher s character than p. Hence the electron - nuclei/nucleus attraction is
strong. This also means their overlaps are also effective.


Give you a question to think about:
For sp3 hybridization, such as methyl group, is considered as electron
donatinggroup. Why?

Check mail for the answer to this question.