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I have been told that the inductive effect is only present in sigma bonds by my teacher, and the book I've referenced also says the same thing.

However, I can't think of why this is. Answers to this question seem to agree with me. But Wikipedia also says that inductive effect only operates through sigma bonds.

So which way is it and why?

Paula

(From Paula Bruice, page 47)

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  • $\begingroup$ The presence of double bonds implies 1)a double faced electronegativity for the C atom 2) resonance (mesomeric effect) eventually at work. This might render I effect propagating through pi bonds not so important to be a subject in introductory chapters. Look at chemistry.stackexchange.com/questions/4904/… where at least one user think as you (and me). $\endgroup$
    – Alchimista
    Commented Nov 8, 2021 at 13:47
  • $\begingroup$ Also, a couple of considerations I do: 1 statements you mentioned are about sigma and pi, not really about single & double. 2 a double bond is anyway a reservoir, it logically damps the I effect propagation through bonds. Like you need water or dump water in a tank placed between two pipe lines. $\endgroup$
    – Alchimista
    Commented Nov 8, 2021 at 13:56
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    $\begingroup$ It's just terminology. Electron donation or withdrawal through the sigma system is termed "inductive". Electron donation or withdrawal through the p-orbitals of a pi system is termed "resonance". $\endgroup$
    – ron
    Commented Nov 8, 2021 at 14:02
  • $\begingroup$ @ron not really / not the point. In fact my damping example refer only to the inductive part,normally negligible. The answer is given by user Zhu in the thread I've linked just above. $\endgroup$
    – Alchimista
    Commented Nov 8, 2021 at 14:32
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    $\begingroup$ @Alchimista I don't think there is any reason to doubt that inductive effect would work through the sigma bond in a double bond as the physics involved is the same, so I've edited the question (and Zhu's answer also gives an example though ron has contested that, but I don't believe he disagrees either with the claim that inductive effect works through sigma bonds of double bond, just that the given example is wrong). Actually I had misinterpreted Zhu's answer earlier, now I understand that he was also only talking about inductive effect through the sigma bond in a double/multiple bond. $\endgroup$
    – Amadeus
    Commented Nov 9, 2021 at 9:03

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