Chemical bonds adjacent, alignment

As already discussed, El and E2 eliminations differ, in part, by the electronic nature of the mechanism. Specifically, El eliminations depend on cationic intermediates, whereas E2 eliminations depend on anionic intermediates. This difference, however, does not eliminate the mechanistic similarities of these reactions as related to the necessary alignment of adjacent chemical bonds. While, as shown in Figure 6.4, El eliminations require alignment of a carbon-hydrogen bond with an adjacent empty p orbital, E2 eliminations, as shown in... 

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