Our teacher told us that a carbocation connected to 3 cyclopropane rings is among the most stable carbocations. But I am unable to understand how, as resonance (the most important factor governing stability) is absent. How did other factors bring so much stability?

  • 2
    $\begingroup$ It is not called ‘three degree’, it is tertiary. Likewise, they are secondary and primary carbocations. The degree notation should have died out a long time ago. $\endgroup$
    – Jan
    Dec 22 '18 at 5:34
  • $\begingroup$ Related: chemistry.stackexchange.com/q/48264/54655 $\endgroup$ Dec 22 '18 at 5:57
  • 1
    $\begingroup$ chemistry.stackexchange.com/q/19090 Half-way dupe. If I vote to close it will be close-hammered because of my badge so I will leave it to others to decide if this is dupe-y enough. $\endgroup$
    – Jan
    Dec 22 '18 at 5:59

Your teacher is correct, that

a carbocation connected to 3 cyclopropane rings is among the most stable carbocations.

This because of various electrical effects, such as:

  1. The Inductive Effect

  2. Resonance

  3. The Mesomeric Effect

  4. Electromeric Effect

  5. Hyperconjugation

Here's a link for you, to study them: Click Here. Please make sure that you learn this correctly and from standard resources, in order to avoid confusion.

There may be a little confusion between mesomeric effect and resonance effect, so here's another link just to avoid confusion. : refer to the answer by Maria Dar

Please, do ask your teacher to help you understand this topic better :-)

  • 3
    $\begingroup$ To state the blooming obvious, only one of those effects has anything to do with cyclopropylmethyl carbocations. Further, are you affiliated with that study link site because it may be considered spammy. $\endgroup$
    – Jan
    Dec 22 '18 at 6:00
  • $\begingroup$ It is spammy as it is really bizarre to start speaking of electronic effects in chemical reactions than afterwards recalling what molecules are :) But the user invite to study standard resources, this is also true $\endgroup$
    – Alchimista
    Dec 22 '18 at 13:18

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