Maximum overlap, hybrid orbitals methods

The Hiickel method is a simple semi-empirical method for determining approximate LCAO molecular orbitals to represent delocalized bonding in planar molecules. It treats only pi electrons and assumes that the framework of sigma bonds has been treated separately. As an example we consider the allyl radical, CH2 = CH - CH2.. If the plane of the molecule is the xy plane, each carbon atom has an unhybridized 2pz orbital that is not involved in the sigma bonds, which are made from the Isp hybrids in the xy plane with the appropriate rotation of the coordinate system at each atom to provide maximum overlap. We construct linear combinations from the three orbitals, as in Eq. (21.6-2). 

Randic and Maksi6 have reviewed the maximum-overlap method of describing the hybridization of bonded atoms, and a number of cyclopropane and cyclobutane derivatives are included. The method has also been applied to benzocyclopropene and benzocyclobutene. One measure of the hybridization of the bonding orbitals of carbon is the magnitude of the and... 

Represent the bonding in the angelic add molecule by using the method in Figure 11-19 to indicate hybridization schemes and orbital overlaps. What is the maximum number of atoms that can lie in the same plane ... 

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