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9.12 Hybrids Including d-Orbitals
•d-orbitals can be involved in the hybridization
at central atoms from the third or later periods
of the table which form expanded octets
•sp3d-hybridization –a combination of one s,
three pand one dorbitals (used to describe the
trigonal bipyramidal e-arrangement)
•sp3d2-hybridization –a combination of one s,
three pand two dorbitals (used to describe the
octahedral e-arrangement)Fig. 9.37, 9.38
•Identification of the hybridization scheme
–draw the Lewis structure and identify the electron
arrangement
–use the following correspondence
Example: What is the hybridization at the Cl
atom in ClF3.
1. Lewis structure: ntot=28, nrem=22, nneed=20
nneed<nrem ⇒⇒ 2extra e-(place at the central atom)
⇒trigonal
bipyramidal e-
arrangement
⇒sp3d -
hybridization
2. 2lone pairs + 3bonded atoms = 5
9.13 Multiple Carbon-Carbon Bonds
•In molecules with more than one central atom,
the hybridization is determined individually for
each central atom
Example: Benzene, C6H6
Each Catom in benzene has a trigonal
planar electron arrangement (0lone
pairs + 3bonded atoms = 3)
⇒sp2-hybridization for all Cs
The σσ-skeleton is formed by the sp2hybrids of the Cs
and the s-orbitals of the Hs
Three ππ-bonds are formed from the sideways overlap of
the unhybridized p-orbitals of the Cs
The resonance spreads the ππ-bonds over the entire ring
The molecule is flat, because such geometry provides for
the best overlap between the p-orbitals
Fig. 9.44, 9.45, 9.46
