1. Unsaturated Carbon Hybridization and Pi Bonding

2. Saturated HC: sp3 hybridization
sp3 4 Si Bonds 4 equal sp3 orbitals forming 4 equal Sigma bonds

3. Double bonds are…
Not: Two sigma bonds together! – tetrahedral corners too far apart to overlap

4. Alkenes: sp2 Hybridization
one s electron is transferred to the empty p orbital
1 s and 2 p orbitals fuse to form
3 x sp2 orbitals and 1 x p orbital

5. Sp2 Hybrid orbitals
p sp2 1 Pi will form 3 Si Bonds

6. Ethene orbital model

7. Double bonds are 1 central, axial Sigma bond
1 sidewise, parallel Pi bond

8. Pi – bonds are formed by the sideways overlap of p- orbitals
Never on the internuclear axis, but above and below
One (!!!) Pi bond is above and below the sigma bond
Weaker than sigma!

9. Pi bond drawing guide Disregard cis/trans
Si- bonds are white blobs along axis
Pi-bonds are shaded in, vertical blobs above and below Si-bonds

10. Alkyne: sp-hybridization
one s electron is transferred to the empty p orbital
s and 1 p orbitals fuse to form
2 x sp orbitals and 2 x p-orbital

11. Sp Hybrid orbitals
p p sp 2 Pi Bonds 2 Si Bonds

12. Orbital Model of Alkyne

13. Triple bond are composed of
1 central, axial Sigma bond
2 sideways, parallel Pi bonds

14. C- Hybridization Overwiew
Type of hybrid
Atomic orbitals used
Number of hybrid orbitals formed
Type of bonds
Aufbau Chart
sp3
s, p, p, p
4 sp3
4 sigma
sp2
s, p, p + extra 1p
3 sp2
3 sigma
1pi sp
s, p +
extra 2p
2 sp
2 sigma
2 pi

15. Reactions and Orbitals
Sigma bonds are strong: connect the Carbon skeleton
Pi bonds are weaker
When double bonds are broken, it means the Pi bond is broken….

16. Drawing Practice
Draw the Orbital Model of
1,2-Butadiene
2-Butyne

17. middle shows hybridization

18. plastic recycling