Benzene orbital hybridization model

According to the orbital hybridization model benzene has six tt elec Irons which are shared by all six sp hybridized carbons Regions of high TT electron density are located above and below the plane of the ring... 

FIGURE 113 (a) The framework of bonds shown in the tube model of benzene are cr bonds (b) Each carbon is sp hybridized and has a 2p orbital perpendicular to the cr framework Overlap of the 2p orbitals generates a tt system encompass mg the entire ring (c) Electrostatic potential map of benzene The red area in the center corresponds to the region above and below the plane of the ring where the tt electrons are concentrated... 

As pointed out in Chapter 7, the atomic orbital (valence bond) model regards benzene as a resonance hybrid of the two structures... 

In Section 6-5 an atomic model of benzene was discussed in some detail. Each carbon in the ring was considered to form three coplanar s/A-hybrid a bonds at 120° angles. These carbon-carbon and carbon-hydrogen a- bonds use three of the four valence electrons of each carbon. The remaining six carbon electrons are in parallel p orbitals, one on each of the six carbons. Each of... 

A special class of cyclic unsaturated hydrocarbons is known as the aromatic hydrocarbons. The simplest of these is benzene (C6H6), which has a planar ring structure, as shown in Fig. 22.11(a). In the localized electron model of the bonding in benzene, resonance structures of the type shown in Fig. 22.11(b) are used to account for the known equivalence of all the carbon-carbon bonds. But as we discussed in Section 14.5, the best description of the benzene molecule assumes that sp2 hybrid orbitals on each carbon are used to form the C—C and C—H a bonds, while the remaining 2p orbital on each carbon is used to form 77 molecular orbitals. The delocalization of these 1r electrons is usually indicated by a circle inside the ring [Fig. 22.11(c)]. 

A modern model of benzene Since the time of Kekul6 s proposal, research has confirmed that benzene s molecular structure is indeed hexagonal. However, an explanation of benzene s unreactivity had to wait until the 1930s when Linus Pauling proposed the theory of hybrid orbitals. When applied to benzene, this theory predicts that the pairs of electrons that form the second bond of each... 

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