Zigzag skeletal structures

We can use these same principles to determine conformations and relative energies for any acyclic alkane. Because the lowest energy conformation has aU bonds staggered and all large groups anti, alkanes are often drawn in zigzag skeletal structures to indicate this. 

Acyclic molecules can also be represented by skeletal structures. In a skeletal stmc-ture of an acyclic molecule, the carbon chains are represented by zigzag lines. Again, each vertex represents a carbon, and carbons are assumed to be present where a line begins or ends. 

Useful information about the stereoregularity and the conformation of the polyvinyl chloride molecule has been obtained from infrared spectra [5i]. For the key bands the C —Cl stretching bands are used. They are coupled with the skeletal deformation vibrations and are conformation sensitive. Fig. 1 shows the C —Cl stretching frequencies of syndiotactic polyvinyl chloride. The various conformations of the syndiotactic and atactic polyvinyl chlorides and their model compounds have their characteristic C —Cl stretching frequencies [5i]. These results clearly show that the syndiotactic PVC takes the extended zigzag structure and the atactic part causes the chain folding. The possibility of utilizing the backbone vibrations for the conformation study has not been explored for PVC. 

A simplified structure called the skeletal formula is a carbon skeleton in which carbon atoms are represented as the end of each line or as comers in a zigzag pattern. The hydrogen atoms are not shown, but each carbon is understood to have bonds to four atoms, including hydrogen. 

A simplified structure called the skeletal formula shows the carbon skeleton in which carbon atoms are represented as the end of each line or as comers. The hydrogen atoms are not shown, but each carbon is understood to have bonds to four atoms. For example, in the skeletal formula of hexane, each line in the zigzag drawing represents a single bond. The carbon atoms on the ends are bonded to three hydrogen atoms. However the carbon atoms in the middle of the carbon chain are each bonded to two carbons and two hydrogen atoms (see Figure 11.2). 

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