For the following anion, which C-C bond would you expect to be longest?

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I know sp3-sp2 would a longer C-C bond than sp2-sp2. But I don't understand how to factor in C2-C1 bond where it's an sp2 hybridized carbon to the anion carbon (C1), which I assume would be CH4- (methyl group) bonded to the sp2 hybridized (C2)carbon. Help please

Thank you

1 Answer
Mar 9, 2018




Bond between C5-C6 experiences no resonance charge, and therefore is the only bond option that has no double bond character.

All of the other C-C bonds listed experience resonance with the negative charge about the species, and therefore, exhibit partial double bond character, making them shorter than the C5-C6 bond which ONLY experiences SINGLE BOND character.