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Questions tagged [stability]

Applied to a chemical species, the term expresses a thermodynamic property in reference to a standard, stating that one state is lower in energy than another. The tag should be applied to questions seeking answers with respect to the stability (or instability) of a certain chemical species, molecular entity and/or electronic structure. It must not be applied to questions about the reactivity of particular chemical species.

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2
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1answer
1k views

Predicting major product of a reaction with nitrous acid

$\hspace{4.5cm}$ For the above reaction I am asked to predict $\ce{X}$, the major product. Of the options given, I thought product (1) would be correct, seeing as how it has the most stable ...
7
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1answer
3k views

Is the phenyl cation or ethynylium more stable?

I recently gave an exam and I received an interesting question to which I believe the answer is wrong. Given two compounds, a benzene molecule with carbocation at one of its constituting carbon atoms ...
8
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1answer
661 views

Why are bromine oxyanions uncommon?

Sodium hypochlorite is used in bleach, calcium hypochlorite is used in public swimming pools, ammonium perchlorate is used in solid rocket fuel. Sodium periodate is used in the cleaving of syn-...
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0answers
2k views

What is the most stable oxide of Fr?

I read that the heavier alkali metals, like K, Rb, and Cs all prefer to form superoxides. Since Fr is the heaviest alkali metal, I assumed it would follow the same trend as the previous alkali metals, ...
3
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1answer
665 views

Which is the better leaving group in the following Cannizzaro reaction?

In the given mechanism, is it correct to prefer hydrogen as a better leaving group than the formyl group? The negative charge on an sp2 hybridized carbon, with the carbonyl group attached to it, ...
4
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1answer
5k views

Why are anti aromatic compounds unstable?

Just like aromatic compounds, anti aromatic compounds have several resonance structures and some of them are also conjugated ( 1,3-cyclobutene). Why is it that just having 4n electrons makes them ...
11
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1answer
6k views

Why are 7-membered rings less likely to form than 5- and 6- membered rings?

I see 5- and 6-membered ring products as the major products even when 7-membered rings are possible. Why is that 5- and 6-membered rings are more likely to form than 7-membered rings? Is it even true? ...
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1answer
126 views

Why only the unstable resonating structure proceeds in the reaction?

For example, in the given image, I have starred the step where the relatively unstable resonating structure proceeds forward in the reaction. Why?
21
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1answer
11k views

Stability Comparison between the Tropylium and Tricyclopropylcarbinyl Carbocation

Why is the Tropylium carbocation less stable than the tricyclopropylcarbinyl carbocation? The tricyclopropylcarbinyl carbocation undergoes a sigma-tropic rearrangement whereas tropylium is highly ...
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1answer
4k views

Confusion in finding electrophilic centre

In the compound CH3-CH2-CN the electrophilic centre according to my NCERT TEXTBOOK(class 11) is the carbon of cyanide but I think it should be the the carbon adjacent to cyanide since, during bond ...
8
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3answers
470 views

Is there any possibility of tautomerisation to en-ol form?

In the picture, you can see the bridge whose end points are in para relation (for making the image clear). Now, what my friend said is that there is no possibility of tautomerisation as there is no H ...
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0answers
704 views

Thermodynamic control or kinetic control?

In my notes, it is written that the case 1 product will be major one. The explanation given is as follows:- However, since the pi clouds of alkenes are perpendicular to each other, the resonance ...
4
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3answers
420 views

Why is the hypoiodite anion unstable in solution, whereas hypochlorite is relatively stable?

$\ce{Cl2}$ and $\ce{Br2}$ can disproportionate in a cold, aqueous, basic environment to form $\ce{ClO-}$ and $\ce{BrO-}$ respectively, yet $\ce{I2}$ directly forms $\ce{IO3^-}$. Why isn't $\ce{IO-}$ ...
7
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1answer
681 views

Why is ICl5 unstable?

For the question Why is $\ce{ICl5}$ unstable? my textbook gave an answer of $\ce{ICl5}$ has too many highly electronegative chlorine atoms present on the central iodine. But how does having ...
12
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2answers
471 views

Why quaternary nitrogen but not tertiary oxygen?

Why do quaternary ammonium ions with a partially positive nitrogen form fairly readily and are often stable but tertiary oxygens, apparently called oxonium ions, are more rare/less stable? The trend ...
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0answers
58 views

Can 0-Carborane be stored at room temperature?

I am a physics post-doc at Oak Ridge National Lab (with a bit more training in chem than the average physicist). I ordered a small sample of o-Carborane from Sigma-Aldrich to test for doping liquid ...
3
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1answer
547 views

I am confused about the stability of carbanion III and IV in the image

I am confused about the stability of carbanion III and IV in the image, I think III is more unstable because of electron donating effect (+R) of -OCH3 group but my book says III is more stable than ...
14
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1answer
575 views

Why can't antiaromatic compounds just escape planarity and become non-aromatic to avoid destabilization?

Why can't just all anti-aromatic systems lose planarity (and hence conjugation) and be non-aromatic like cyclooctatetraene ? ...
2
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1answer
641 views

Dependence of carbocation stability with respect to the length of alkyl group

Which carbocation is more stable, the ethyl carbocation or n-propyl carbocation? What is the effect of alkyl group length on the stability of a carbocation?
2
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0answers
105 views

Why doesn't H-O-O-O-O-O-O-O-O-H exist? [duplicate]

The question has its roots in why only carbon mainly shows catenation. I don't see why such a compound cannot be formed. Why don't we have a whole branch dealing with such compounds other than organic ...
2
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1answer
2k views

Nitrogen molecule vs carbon-carbon triple bond stability [duplicate]

Why does the triple bond in the nitrogen molecule convey stability, whereas a triple bond between carbon atoms conveys instability?
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3answers
968 views

Which tautomer of hexane-2,4-dione is more stable?

Which tautomer will be more stable? Both 1 and 2 show intramolecular hydrogen bonding and form 6 membered cyclic ring, thus increasing the stability. I think I need to compare the effect of the two ...
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2answers
5k views

Why is the eclipsed conformer more stable than the bisected conformer in 1-butene?

I have just started learning conformational analysis, and a major doubt came into my mind. In simple alkanes such as ethane, the staggered conformer is much more stable than the eclipsed conformer. ...
3
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1answer
795 views

Is Tollen's test safe?

Tollen's test is an important test to distinguish between aldehyde and ketone. $$\ce{2 [Ag(NH3)2]+ + RCHO + H2O → 2 Ag(s) + 4 NH3 + RCO2H + 2 H+}$$ But is this reaction safe? Is there any threat in ...
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0answers
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What is the order of stability of the following carbocations?

What is the order of stability of the following carbocations? I think that it is clear thatt the first two are more stable than the last 2 as they involve resonance in ring, i.e. the mesomeric ...
2
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1answer
3k views

Which complexes are stable: ammine complexes or carbonyl complexes?

According to Wikipedia, A spectrochemical series is a list of ligands ordered on ligand strength and a list of metal ions based on oxidation number, group and its identity. $$\ce{I- < ...
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2answers
10k views

Why Cu+ is unstable in aqueous medium?

This was one of the question that was given in the school exam. But what I am expecting is that $\ce{Cu+}$ attains a $d^{10}$ configuration by losing one electron from s-subshell. Since it has fully ...
5
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1answer
30k views

Order of reactivity of carbonyl compounds towards nucleophilic addition

Arrange the following according to reactivity towards nucleophilic addition reaction: I have already seen this post regarding the reactivity. It helped me to some extent. $\ce{Cl}$ increases the ...
14
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2answers
7k views

Why is sulfur hexafluoride more stable than selenium or tellurium hexafluoride?

I was just reading about p Block elements from two different books. Both books say that $\ce{SF6}$ is extremely stable in 16th group due to steric reasons but my question is why is it more stable than ...
4
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1answer
1k views

Stability of alkenes by hyper conjugation

I have learnt that for carbocations, electrons are delocalized from the $\ce{C-H}$ $\sigma$-bond to the empty p-orbital of carbon. Moreover, alkenes are stabilized by the delocalization of electron ...
10
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3answers
3k views

Why is diene more reactive than alkene?

The chemical reduction of 1,3-butadiene with sodium in alcohol gives mainly the 1,4-addition product that is but-2-ene. Under these condition the isolated double bond are not reduced. This suggest ...
10
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1answer
613 views

Stability of isomers of N4O

I have googled and found that the structure of $\ce{N4O}$ is linear with a positive and negative charge on 2 nitrogen atoms. But, the following structure seems more stable because it fulfils octet for ...
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0answers
39 views

Can there be gaps in autoignition temperatures?

I recently saw a request for solids that auto-ignite between 80C and 160C. I can't find any, and none have yet been suggested. Which leads me to the theoretical question: Is it possible for there to ...
4
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2answers
2k views

Why is the acylium ion stable?

Why is the acylium ion stable? Doesn't the inductive effect of oxygen destabilize it? Compared to an alkyl cation, is an acylium ion more stable or less stable?
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1answer
2k views

Why does Iodine form Cations sometimes?

It is reported that iodine forms compounds like $\ce{(CH3COO)3I}$, $\ce{I(ClO4)3}$ and $\ce{IPO4}$ which contains $\ce{I+}$ and $\ce{I^3+}$ and are not bonded covalently as in interhalogen compounds. ...
6
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1answer
5k views

What is meant by 'stability'?

I'm currently learning about substitution and elimination reactions and to do so I need to learn about bases and nucleophiles. Apparently a good base is an unstable species. What does stability ...
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1answer
208 views

Stability of carbocations

We know that if a structure has all equivalent resonance structures, then it will be highly stabilised. So then why benzylic carbocation is more stable than other cyclic allylic carbocations, though ...
10
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3answers
29k views

Is iron the most stable element in the periodic table?

According to the binding energy per nucleon vs mass number graph, it is observed that iron-56 has the maximum value of binding energy per nucleon ($\pu{8.75 MeV}$). It means that iron-56 is the most ...
18
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1answer
6k views

Stability of carbocations: CF3+ vs CH3+

Is $\ce{CF_3+}$ more stable than $\ce{CH_3+}$? In $\ce{CF_3+}$, there is $\ce{C-F}$ back bonding that increases stability of the carbocations. But -I effect of $\ce{F}$ dominates +R effect and this ...
4
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1answer
223 views

Influence of neighboring fluorine and hydroxyl on carbocation

Which of the 2-fluorobutan-3-yl and butan-2-ol-3-yl carbocations will be more stable? I know that fluorine has a greater electron-withdrawing inductive effect, but what about the resonance effect of ...
0
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1answer
2k views

Why are phosphate-phosphate bonds weaker than phosphate-water bonds?

According to the Wikipedia entry on ATP, ATP is an unstable molecule in unbuffered water, in which it hydrolyses to ADP and phosphate. This is because the strength of the bonds between the ...
14
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2answers
3k views

Why are aromatic compounds so stable?

I've never actually been told deeper reasons for this. In organic chemistry classes (1 and 2) we're usually told that aromatic compounds are very stable whereas anti-aromatic ones are not, and also, ...
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1answer
4k views

Stability of furanose vs. pyranose form of glucose?

I am trying to imagine the cyclization of the Fischer projection of glucose as it forms an $\unicode[Times]{x3B1}$-D-glucofuranose and an $\unicode[Times]{x3B1}$-D-glucopyranose (right now I am trying ...
3
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1answer
166 views

Do hydrogen peroxide stabilizers affect oxidizing ability

I plan to use hydrogen peroxide for a redox reaction in oxidizing $\ce{I-}$ to $\ce{I}$. I found 20 volume hydrogen peroxide as a hair developer, but it contains stabilizer. I imagined these would ...
26
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2answers
2k views

Which of the following is the more stable carbocation?

Which of the following is the more stable carbocation? I thought the 1st carbocation would be the more stable one as the pi-electron density of phenyl group can overlap with the vacant orbital on ...
4
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1answer
2k views

Confused about carbocation stability

For which element 'X' is the carbocation $\ce{CH3-X-CH2+}$ the most stable? A. X = S B. X = N C. X = O I thought since oxygen is the most electronegative among the options, it would create the ...
2
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1answer
135 views

Why highly unstable cyclic boron compounds should be stabilised by two electron reduction?

I am trying to figure out why highly unstable cyclic boron compounds could be stabilised by two electron reduction... My thoughts are because each Boron has an empty p-orbital perpendicular to plane ...
3
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1answer
902 views

Stability of carbocation intermediates: secondary alkane versus primary allyl?

Say I have the following carbocations: The first is secondary; the second is resonance stabilized, but primary. Which is more stable and why? I've been looking around in my textbooks and haven't ...
11
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2answers
4k views

Why is a bridgehead atom bearing a negative or a positive charge unstable?

Why is a bridgehead atom bearing a negative or a positive charge unstable? Is it something with the structure of bridge bonds? I am unable to understand why.
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2answers
2k views

Why is acidic hydrogen peroxide a potent oxidizer?

When hydrogen peroxide acts as an oxidizer it itself is reduced. Broadly this means that the peroxide bond is broken and that water is formed. However, why is there a tendency for hydrogen peroxide ...