Previous Lecture
•Lewis structures
•Formal charge
•Resonance
•Valence bond theory and Molecular orbital theory
•Covalent bond and Polarized covalent bond
•sp3 hybridization
•HOMO and LUMO
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Atomic orbital of Carbon atom
Electron configuration of C
Geometry of methane can be explain through SP3 hybridization.
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What about CH2CH2 ?
Planar structure of ethylene
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Hybridization of 2s and 2Px and 2Py resulting in three SP2 hybrid orbitals.
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C=C bond formation in ethylene:
sigma-overlapping of sp3 orbitals and pi-overlapping of p orbitals
Rotation about the c=c bond?
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Free rotation?
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Cis and Trans Isomers
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HOMO of C=C in ethylene
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Bonding in Ethylene
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HW5: write down the overlapping of AO’s for all bonds in the
following molecules
CH2CHCl
CH3CHCHCH3
CH3COH
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Energy Level
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What about acetylene ?
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Hybridization of 2s and 2Px resulting in two SP hybrid orbitals.
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Overlapping of sp orbitals (one from each carbon) forming one sigma-bond and
overlapping of py and pz (two from each carbon) forming two pi-bonds.
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HOMO of acetylene
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Energy Level
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HW6: write down the overlapping of AO’s for all bonds in
the following molecules
CH3CN
CH3CCBr
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Conclusion
Geometry around C
tetrahedral
trigonal
linear
Hybridization
sp3
sp2
sp
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Other carbon species: carbocation, carbon radical and carbanion
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CH3+
Carbocation
Trivalent
Planar geometry of CH3
sp2 Hybridization with empty p orbital
LUMO of CH3+
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CH3- carbanion
•Trivalent
•Tetrahedral geometry of CH3
•sp3 Hybridization with unshared electron
pair (lone pair electron) in one sp3 orbital
HOMO of CH3S. Wanichwecharungruang
CH3 radical
•Trivalent
•Planar geometry of CH3
•sp2 Hybridization with unpaired electron
in p orbital
HOMO of CH3 radical
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Conclusion
• sp2 and sp3 hybridization: geometry
• cis and trans isomer
• Hybridization in carbocation, carbanion and
carbon radical
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Hybridization - Nitrogen, Oxygen, and Sulfur
Nitrogen - sp3 hybridization
Hybridization - Nitrogen, Oxygen, and Sulfur
Nitrogen -sp2 hybridization
Hybridization - Nitrogen, Oxygen, and Sulfur
Oxygen - sp3 hybridization
Hybridization - Nitrogen, Oxygen, and Sulfur
Sulfur - sp3 hybridization