Timeline for Which of the canonical structures contributes more to resonance hybrid?
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| May 13, 2021 at 6:00 | history | edited | Buck Thorn♦ | CC BY-SA 4.0 |
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| Sep 24, 2020 at 16:49 | comment | added | user85426 | From a fundamentally, philosophical level, what really does existence mean anyway? How do we really know that the true structure exist even when we ourselves are not sure of our own existence? Is this a phone I am typing on? Is there really a forum? Am I really talking to someone else from the other end of the globe? Well, I will not truly know. Do resonance structures exist? Well, if my existence could be doubted, does anything actually exist? | |
| Sep 24, 2020 at 16:44 | comment | added | user85426 | Sorry if whatever I said offended you, it is just how I usually talk. Thank you for responding. Of course, I agree that resonance structures are in fact, as you said, "mathematical tricks" (or I would like to call them tools). But when we are talking about the term "existing", there is really no scientific definition for the term. Of course they could not be isolated but that does not mean that they are not a representation of the true structure. In that sense, they very much exist. | |
| Sep 15, 2020 at 23:20 | comment | added | Martin - マーチン♦ | @user85426 Resonance structures are here mathematical tricks just as orbitals are; that is not only my point of view. They do in none of the accepted definitions of stable exist. I respect that you gave a different view and you can disagree with me, but there won't be convincing me. Please don't call me dear friend, that is a term of endearment that has to be earned otherwise it sounds condescending. | |
| Sep 15, 2020 at 13:54 | comment | added | user85426 | Ionic resonance structures, I agree, they do exist. It is with ionic resonance structures that we could explain things like HF2- and B2H6. However, in this case, we should ask ourselves, is such an ionic resonance structure stable? Well, no, because a CH3- the structure is inherently unstable and the C-H bond has hardly any ionic character. | |
| Sep 15, 2020 at 13:52 | comment | added | user85426 | My dear friend @Martin-マーチン, there are more or less significant resonance structures. Only when we know the more significant resonance structures can we begin to predict the properties of a molecule. Sure, resonance structures could not be isolated but that does not mean they do not "exist" since the real structure is essentially a superposition of all possible resonance structure but adding a different linear factor to each structure. | |
| Aug 23, 2019 at 9:48 | comment | added | Martin - マーチン♦ | With charge separated structures I mean those representing ionic bonds, i.e. in the way like $\ce{[H-CH3 <-> H+\quad^-CH3]}$. These do have non-negligible contributions and are necessary for complete description. What you describe in your answer is approximated beyond the useful, even if you disregard that resonance structures do not exist. | |
| Aug 22, 2019 at 16:23 | comment | added | Fancy-Toon | but don't you think it's not possible to make charge separated structures here .. I mean the "O" atom should be pi bonded in such a case ... how can a negative charge develop over the "O" atom..?? | |
| Aug 22, 2019 at 15:51 | comment | added | Martin - マーチン♦ | A complete set is all possible resonance structures. The one in the question is by far not complete, it is missing the charge separated structures. The only part in which it could be considered complete is the pi system. | |
| Aug 22, 2019 at 15:27 | comment | added | Fancy-Toon | what's a complete set ?.. It must be the pack of all the possible resonance structures of a single compound..in this case it looks complete.. | |
| Aug 22, 2019 at 13:54 | comment | added | Martin - マーチン♦ | I can only reiterate: There is no such thing as a more (or less) stable resonance structure. They simply do not exist on their own and are only a tool for approximating the electronic bonding situation; only a complete set would actually do that. This answer is unfortunately wrong. | |
| Aug 21, 2019 at 14:02 | history | answered | Fancy-Toon | CC BY-SA 4.0 |