Molecular orbitals sp3 hybridization and

Know the meaning of molecular formula, structural formula, structural (or constitutional) isomers, continuous and branched chain, formal charge, resonance, contributing structures, sigma (a) bond, sp3-hybrid orbitals, tetrahedral carbon. 

In line with Higashimura s view34 that carbenium ions are not strictly sp2 hybridized and that they retain some sp3 character, a more nucleophilic G would be expected to induce more sp3 character to the growing cation. Pronounced sp3 character of the carbenium ion would prevent orbital overlap, i.e., the formation of transition state leading to transfer, and thus to increase in molecular weight. 

Figure 5.4. The highest occupied molecular orbital of a Si911,2 dimer cluster. The top two silicon atoms comprise the surface dimer, and the remaining seven Si atoms contain three subsurface layers which are hydrogen terminated to preserve the sp3 hybridization of the bulk diamond cubic lattice. The up atom is nucleophilic and the down atom is electrophilic.

The Cl—F and Cl—Cl bonds in the cation are then formed by the overlap of the half-filled sp3 hybrid orbitals of the central chlorine atom with the half-filled p-orbitals of the terminal Cl and F atoms. Thus, by using sp3 hybridization, we end up with the same bent molecular geometry for the ion as that predicted by VSEPR theory (when the lone pairs on the central atom are ignored) 

The reacting orbital system needed to include all the bonds being formed or broken is made up in the reactant from a basis consisting of a p orbital on each of the four carbon atoms, and in the product of p orbitals on each of the two it bonded carbons and a hybrid orbital, approximately sp3, on each of the two carbons linked by the newly formed a bond. Figure 11.6 illustrates the basis functions and the molecular orbitals that arise from them. 

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