Ethylene, electrostatic potential maps structure

The structure of ethylene and the orbital hybridization model for its double bond were presented m Section 2 20 and are briefly reviewed m Figure 5 1 Ethylene is planar each carbon is sp hybridized and the double bond is considered to have a a component and a TT component The ct component arises from overlap of sp hybrid orbitals along a line connecting the two carbons the tt component via a side by side overlap of two p orbitals Regions of high electron density attributed to the tt electrons appear above and below the plane of the molecule and are clearly evident m the electrostatic potential map Most of the reactions of ethylene and other alkenes involve these electrons... 

Benzophenone, structure of, 697 Benzoquinone, electrostatic potential map of, 631 Benzoyl group, 697 Benzoyl peroxide, ethylene... 

When we draw a similar resonance structure for an ,/3-unsaturated carbonyl compound, however, the positive charge is allylic and can be shared by the jS carbon. In other words, the /3 carbon of an ,j8-unsaturated carbonyl compound is an electrophilic site and can react with nucleophiles. A comparison of electrostatic potential maps of ethylene with an a,/3-unsaturated ketone shows that the double-bond carbon atoms of the unsaturated ketone are more positive (more green) than those of the isolated alkene ethylene. 

The following image is an eleetrostatic potential map for ethylene oxide, (CH2)20, a polar molecule. Use the electrostatic potential map to predict the geometry for how one ethylene oxide molecule interacts with another. Draw structural formulas, using the 3D bond notation introdueed in Section 10.4, to show the geometry of the interaction. 

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