Question

benzene question

Answer 1

why is bezene not called 1,3,5-cyclohexatriene to comunicate three doube bondsin a hexagon?

From what i know "resonance hybrid theory" that the delocalized electrons are shared by all six atoms creating a benzene ring, which means there would be no double bond.....


but this question seems to say it does.... unless im wrong

Answer 2

@matt101

Answer 3

1,3,5-cyclohexatriene is actually the IUPAC name for benzene, so it's perfectly okay to use that name.

Like you say, though, benzene is a special case of double bonds due to "conjugation" (which is what the resonance hybrid theory you're talking about is getting at). Basically, because of the organization of the double bonds in benzene (appearing on every other atom), all the carbon atoms adopt the same hybridization state, allowing electrons to become more delocalized and move freely between all the conjugated atoms. This is a more stable state than if you had electrons localized to just one double bond.

In other words, the structure that is implied by 1,3,5-cyclohexatriene makes it easier for us to draw and visualize, but in reality all the carbon-carbon bonds in the ring have some double bond character because of this conjugation that's happening.

Hope that helps!