S-Character and Bond Angle Relationship

$sp, sp^{2}, sp^{3}, dsp^{3}, d^{2}sp^{3}$

FizaBaloch1J
Posts: 41
Joined: Fri Apr 06, 2018 11:01 am

S-Character and Bond Angle Relationship

What does "as the s-character of a hybrid orbital increases, the bond angle increases" mean?

Because sp2 = trigonal planar so bond angle is 120, and then when you go up to sp3= tetrahedral so bond angle decreases to 109.5

So my question is what does s-character mean exactly?? Does s-character increase when you have lower electron densities around a central atom?

KateCaldwell 1A
Posts: 43
Joined: Fri Apr 06, 2018 11:02 am

Re: S-Character and Bond Angle Relationship

S-character is the contribution of the sigma (single) bond in hybridization. In sp^3, there is 25% s-character and 75% p-character, whereas, in sp, there is 50% s-character and 50% p-character. Therefore, the more s-character a bond has, the stronger as well as the shorter bond becomes. S-character refers to hybridization, so I don’t think electron density matters but rather, the amount of atoms attached to the central atom.

Megan Phan 1K
Posts: 31
Joined: Fri Apr 06, 2018 11:04 am

Re: S-Character and Bond Angle Relationship

The s-character means the single bond, or sigma in the hybridization. Like sp, half is s-character and the other half is p-character.Or in sp3 its 1/4 s-character and 3/4 p-character. When there are more s-characters in a bond, the bond grows shorter yet stronger. It's all about the atom amount, just think of the hybridization.

Chem_Mod
Posts: 18896
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 717 times

Re: S-Character and Bond Angle Relationship

s- character is referring to be % contribution of the s-orbital to the hybrid orbital. The higher the % of s-orbitals in the hybrid oribtals, greater the s-character.