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0
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1answer
39 views

Why is C4 of butynone electrophilic?

A question asks whether C4 in 3-butyne-2-one can act as a nucleophile, electrophile, or acid (it can be more than one). The answer is that it can be both electrophilic and acidic. The acidity makes ...
6
votes
3answers
122 views

Why is structure B disfavored?

Our prof only told us that A is favored and B is not getting formed. I thought about the resonance structures and saw a contradiction to that what the prof told us. To be honest I think my argument ...
3
votes
3answers
190 views

Is aniline aromatic - How to treat the lone-pair electrons of nitrogen when applying Huckel's rule?

Why is aniline aromatic? Doesn't it have 8 pi electrons, thereby violating Huckel's rule? The way I see it, there are 6 pi electrons from the benzene ring, and an additional 2 from the sp2 ...
2
votes
1answer
38 views

Do acyl fluorides exhibit resonance donation or inductive withdrawal?

I know that in acyl chlorides, there is partial triple bond character in the C=O bond not because the chlorine is electronically donating (due to size mismatch with carbon) but because the chlorine is ...
4
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4answers
381 views

Is Pyrene Aromatic?

Pyrene doesn't seem to be aromatic. However, sources claim that it is aromatic. Considerations: 1) Pyrene is cyclic. āœ“ 2) Pyrene is flat (planar). āœ“ 3) Pyrene has 16 pi electrons. 4) Every ...
2
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1answer
97 views

Resonance of 4-isopropylbenzenethiol

Can someone draw what the missing structure is? I can't find it.
2
votes
2answers
74 views

Carboxylate “cage” concept

My professor emphasizes the concept of the carboxylate "cage" or the idea that electrons participate in resonance within a carboxylate group such as in the benzoate anion but the electrons in the ...
3
votes
1answer
47 views

Validity of ionic resonance structures

What's wrong with ionic resonance structures? I asked one professor about them once and all he commented was "I've seen them too, and I think they're wrong." Another professor rejected an ionic ...
4
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1answer
68 views

What are the correct resonance structures of bromoethene?

Can anyone explain why my textbook only gives the following resonance structures? I also put two resonance case where the double bond electrons are moved on the individual carbon atoms.
4
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1answer
163 views

Ozone resonance structure: differing opinions

I've always thought that the two-form resonance structure of ozone was the scientific concensus (from Wikipedia]: Then today I found two other opinions. A three-form structure: And a four-form ...
2
votes
3answers
96 views

What are the most important resonance structures of 5-aminocycloheaxa-2,4-dienone?

Here attached is a question from my exam. My TA removed 1 point out of 7 for a reason. Can anyone decipher for what? There's the writing in red but it is illegible to me. I don't understand to what he ...
0
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1answer
47 views

Delocalization of positive charge

How is positive charge delocalized? I understand how negative charge can be delocalized. Electrons are mobile and they can move around. But what about positive charge? For example, consider this ...
-2
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1answer
61 views

O=Cl=O and O-Cl-O in a ring are not resonance structures?

Resonance structures are about moving electrons to form anions, cations, and new bonds. Structural isomers can be resonance structures. For example take phenyl ketone. Of course you can form ...
0
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1answer
69 views

How to draw resonance structures for CH3COCN

What are the resonance structures of $\ce{CH3COCN}$ molecule?
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2answers
161 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
197 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 ...
2
votes
2answers
247 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
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1answer
85 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 ...
0
votes
1answer
49 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 $\ce{sp^2}$ ...
8
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0answers
152 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 ...
2
votes
1answer
66 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 ...
0
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1answer
129 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 ...
6
votes
1answer
118 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 ...
2
votes
2answers
212 views

Why does having equivalent resonating structure give more stability?

If we take a phenolate ion ($\ce{C6H5O-}$) and an acetate ion ($\ce{CH3COO-}$) which one would be more stable? Although the Phenolate ion has more(4) resonating structure compared to acetate ion(2), ...
1
vote
1answer
270 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: $\ce{-CONHCH3}$, ...
3
votes
3answers
312 views

Benzene and resonance

In my book, to explain the structure of benzene, it referred to the idea of resonance: "The idea of resonance is that actual molecule is a definite structure that is a hybrid of two theoretical ...
3
votes
1answer
75 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
200 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 ...
7
votes
1answer
563 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 ...
8
votes
3answers
864 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 ...
2
votes
0answers
370 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 -OH group is highly reaction favoring. From what I understand, this ...
0
votes
2answers
644 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 ...
4
votes
1answer
338 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
235 views

Can a polymer have different resonance structures?

Several organic compounds have resonance structures, but can a polymer have resonance structures?
3
votes
4answers
229 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
804 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?
6
votes
1answer
288 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 ...
3
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1answer
984 views

The most stable furan resonance structures?

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?
7
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2answers
209 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 ...
16
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3answers
691 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 ...