A message from our CEO about the future of Stack Overflow and Stack Exchange. Read now.

Questions tagged [resonance]

Resonance refers to the representation of the electronic structure of a molecular entity in terms of contributing structures. The tag should be applied to any question that concern resonance structures or resonance energy. This tag should not be applied to questions about aromatic compounds (use the [aromatic-compounds] tag instead)

Filter by
Sorted by
Tagged with
3
votes
2answers
9k views

Difference between backbonding and hyperconjugation and conjugation [closed]

What is the difference between backbonding and hyperconjugation and conjugation? I mean the basic differences as all are concerned with donation of electrons. What is the most striking effect of each ...
2
votes
2answers
2k views

Nitric acid vs. chloric acid strength

Here the central chlorine atom is best described as $\ce{sp^3}$ hybridized. This makes sense; the molecule is pyramidal. Also, due to the molecule's pyramidal geometry, this rules out the possibility ...
3
votes
2answers
13k views

Does resonance affect the polarity of the molecule?

Ozone is a resonating structure, is it because of its resonance and bent structure that it is a polar molecule? Or Is it because of the formal charges whereby the formal charges determine the ...
0
votes
1answer
322 views

Halogens and the free energy of activation in a resonant benzene system

If we look at the right-hand-side table here: http://en.wikipedia.org/wiki/Hammett_equation, we notice something particular. It appears that the free energy of activation (for example, measured in ...
2
votes
1answer
857 views

Hybridization in Light of Resonance

According to this video: http://www.youtube.com/watch?v=ns4Py96Bkn8&NR=1 1) Is this true? (You might recall I asked a similar question about $\ce{sp^2}$ hybridization implying $\ce{sp^2}$ ...
18
votes
1answer
3k views

Why does depurination happen at a higher pH (or under less harsh conditions) than depyrimidation?

I've always wondered why the N-glycosidic bond, which connects the adenine or guanine purine bases to their sugars, was the easiest to cleave via acid hydrolysis, or why purines have the lowest ...
3
votes
1answer
616 views

Proper Resonance Structures

Would this be proper resonance structures? I know there's a lone pair on the top carbon. Having a carboanion isn't favorable as opposed to a negative formal charge on the more electronegative carbon ...
1
vote
1answer
3k views

Resonance in Cyclohexenone

I don't think that cyclohexenone should have any resonance forms. Moving the double bond around would necessitate moving hydrogens around as well. For example, I know that benzene exhibits resonance (...
12
votes
1answer
5k views

Rationalizing the Planarity of Formamide

In formamide, the nitrogens appear to be $\ce{sp^3}$ hybridized, implying tetrahedral geometry. However, analysis shows that the molecule is actually very nearly planar with bond angles close to 120 ...
3
votes
1answer
298 views

Orbital Electronegativity Considerations in Resonance Structures

After consulting three organic chemistry texts (Wade, Klein, and Brown), only one actually clearly delineates a few guidelines for picking the most significant resonance structure. The others mention ...
5
votes
2answers
8k views

Why is only one lone pair in imidazole delocalised?

I was wondering why only one of the nitrogen lone pairs in imidazole is involved in the delocalized π-system. Specifically, I was wondering why it is that lone pair B in particular is delocalized, ...
1
vote
3answers
2k views

Resonance stabilized carbanion

I am sure that the answer is (b) because I am familiar with the other rings and I think they are showing resonance (and it is a single choice question so it was easy to guess) I wish to know why ...
34
votes
1answer
3k views

Natural Bond Orbital analysis: Significance of stabilization energy determined by 2nd order perturbation

PREFACE: I am no expert on this topic. My questions at the bottom may be off base. I have some experience with symmetry-adapted perturbation theory (SAPT) when it comes to analyzing intermolecular ...
4
votes
2answers
8k views

Why does having equivalent resonance structures give more stability?

Although the phenolate ion has more resonance structures (4) compared to acetate ion (2), acetate is more stable because it has two equivalent resonance structures of same energy. Why does having ...
2
votes
1answer
8k views

Understanding Mesomeric Effect

I am getting confused between the type of mesomeric effect (+M or -M) shown by compounds containing $\ce{-COX}$ where $\ce{X}$ is an electronegative element. Examples: $\ce{-CONHCH3}$, $\ce{-COOCH3}$,...
7
votes
2answers
4k views

What is the “resonance hybrid” of benzene?

In my book, to explain the structure of benzene, it referred to the idea of resonance: The idea of resonance is that the actual molecule is a definite structure that is a hybrid of two or more ...
4
votes
1answer
262 views

Can polyatomic ions (CO₃, PO₄, SO₄, NO₃) be considered conjugated systems?

From my perspective these resonance structures allow these specific polyatomic ions to act as donor-acceptor molecules. Many donor-acceptor molecules also tend to be conjugated systems because they ...
2
votes
1answer
7k views

Is acetate a weak base due to its resonance structure?

I just read that acetic acid is an exception to the general idea that the conjugate base to a weak acid is a strong base. The example says that the conjugate base of a weak acid will only be strong ...
13
votes
2answers
8k views

Resonance stability: ester vs. thioester

My problem set solution cites: "Although sulfur is less electronegative than oxygen, overlap is a more important consideration. Sulfur is a member of the third period. As a consequence, a ...
3
votes
2answers
4k views

Order of positive mesomeric effect of halides

I learned that the order of $+M$ effect (mesomeric effect) for halogens is as follows: $\ce{F} > \ce{Cl} > \ce{Br} > \ce I$. I wonder why this is so?
11
votes
1answer
8k views

Does unsubstituted benzoic acid not show resonance due to steric effects?

My book says that benzoic acid does not show resonance as the carboxylate anion and the benzene ring are not in the same plane due to steric effects. But there aren't any large groups in the ortho ...
15
votes
5answers
17k views

Is oxygen with a positive charge more stable? (comparison of canonical structures)

Which of the contributing structures of the resonance below is more stable? I'm watching a video lecture by a professor of my college where he puts this question to the class. The class ...
13
votes
3answers
9k views

Competing resonance and inductive effects in a substituted benzene

A molecule of phenol is much more inclined to under go an electrophilic substitution reaction than a molecule of benzene because the $\ce{-OH}$ group is highly reaction favoring. From what I ...
0
votes
2answers
4k views

Predicting electronic geometry, observable geometry, and hybridization for any atom in a molecule

Can someone please explain the intuition around the answers to this problem: I'm finding it very confusing because it seems like you have to nitpick between two resonance structures to get the ...
3
votes
2answers
1k views

Are aromatic amines or amides less basic?

When the lone pair of an amino group $\ce{R-NH2}$ is involved in resonance, its basicity decreases. But, between conjugation with carbonyl group $\ce{R}=\ce{R'CO}$ or resonance with benzene $\ce{R} = \...
10
votes
2answers
4k views

Which are the differences between resonance Raman and fluorescence?

If the fluorescence is the re-emitting of a photon with a larger wavelenght due to the transition from a higher energy state to a lower energy state the case of resonance Raman (where there aren't any ...
5
votes
3answers
738 views

Can a polymer have different resonance structures?

Several organic compounds have resonance structures, but can a polymer have resonance structures?
20
votes
2answers
9k views

How to rationalise the resonance structures and hybridisation of the nitrogen in a conjugated amine?

I was given the first structure, and then drew the other 5 resonance structures: First of all, are they correct? ChemBioDraw had some complaints, but as far as I can see there's the same number of ...
3
votes
4answers
830 views

large wavelength range and list of x/y numerical data points of elements

I'm trying to get a set of FTIR or (FTIR like range) x/y numerical data points for a couple of elements, namely Silver, Platinum, Palladium, Gold and Sodium. I've looked on line and found images ...
0
votes
1answer
2k views

Does resonance apply to NO₂⁺?

My textbook said $\ce{NO2+}$ and $\ce{NO2-}$ both have resonance structures, now I am a little bit confused since I cannot figure out the resonance structure for $\ce{NO2+}$. What is it?
11
votes
1answer
2k views

Resonance in carbocation derived from allenes

During a reaction if addition on one of the $\pi$ bonds of an allene (containing even number of $\pi$ bonds like $\ce {H2C=C=CH2}$) takes place then a carbocation is formed. To decide the position of ...
16
votes
3answers
35k views

Bond order for carbonate ion for resonance

I saw in a textbook that for carbonate ion, there are 3 resonance forms and the bond order is 1 and 1/3. So in general, how should we calculate the bond order for resonance structures? Is there any ...
6
votes
1answer
7k views

What is the order of stability of the resonance structures of furan?

I want to know which are the most stable furan resonance structures. I know that structure number 1 is the most stable, but which one comes after?
15
votes
2answers
849 views

Edges of graphite

I've been asked this question a few times, and while I think I know the answer, I'd like to know more. Graphite, as we know, is a sheet polymer. Since polymers are bound to be finite by physical ...
32
votes
3answers
2k views

Pauli exclusion principle and resonance

I've always been a bit uncomfortable with the concept of more than two electrons in a single orbital-like region(probability-wise) which occurs in resonance. This seems to disobey Pauli's exclusion ...