How #"degrees of unsaturation"# are associated with a #C_8H_10# formula?

1 Answer
Mar 16, 2017

Answer:

Well the formula #C_8H_10# has 4 degrees of unsaturation ......

Explanation:

The saturated formula would be #C_8H_18#, and thus the given formula #C_8H_10# has #"4 degrees of unsaturation"#.

And each degree of unsaturation CORRESPONDS to an olefinic bond, i.e. #C=C# OR a RING JUNCTION.

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And thus the pictured #"xylene"#, as well as any one of its other 2 isomers (which are?) could correspond to the formula. And by my count #"xylene"# has #8xxC-C# #sigma# bonds, #10xxC-H# #sigma# bonds, and, formally, #3xxC-C# #pi# bonds.........

By joining and fusing rings, we could form a structure where the distinction between #sigma# and #pi# bonds are less ambiguous, however, these would be less common structures than the benzene derivative.

Note that the #"degree of unsaturation"# is a very useful criterion with which to assess organic molecules.