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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4answers
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Which molecule is more acidic: CHF3 or CHBr3?

I know that fluorine is more electronegative than bromine. However, because of the size of bromine, it is more stable with a negative charge. In the case of $\ce{HF}$ vs. $\ce{HBr}$, to me, $\ce{HBr}$ ...
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0answers
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Are there any stable complexes where an (N-unsubstituted) imine is bound eta^2 to a (late) transition metal?

I've been looking for an example of a stable complex where a $\ce{C=N}$ is coordinated $\eta^2$ to a (late) transition metal, but could not find any. Do they exist at all? For $\ce{C=C}$ there are ...
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1answer
2k views

Stability by using charge/radius rule

I found a question Which is more stable among the following? (a) $\ce{CaCO3}$ (b) $\ce{MgCO3}$ Answer : (a) Explanation was given as: "$\ce{Mg^2+}$ has smaller radius than $\ce{Ca^2+}$ and thus $...
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0answers
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Which factor drives the stability in chelated complexes? [duplicate]

Which factor drives the stability in chelated complexes? Stability, I guess, is supposed to be associated with a release of energy. Does something like this happen in chelated complexes?
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1answer
600 views

How to compare stability of following two alkenes [duplicate]

How to find which alkene is more stable ?. As same number of hydrogens are added across the double bond so I am not able to use the fact that more substituted alkene is more stable. I was initially ...
0
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2answers
7k views

Why and how carboxylate ion has greater stability than carboxylic acid?

I found it written in my textbook. I think it's a misprint, I can't think of any logic behind this statement. I've only learned that ion is less stable specie so carboxylate ion cannot be more stable ...
0
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1answer
410 views

Stability order of octahydrobiphenylenes

I am facing trouble in the following question What is the stability order of the following compounds? In my view cis is less stable than trans. So if prior groups are on the same side of the ...
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2answers
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Why are radical intermediates are more stable on tertiary carbons?

Is this because there's more electron density? More carbons around means the tertiary carbon "has more electrons around it"?
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2answers
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Why is isoindole unstable?

According to this paper, isoindole is unstable because the 1-carbon in the isoindolidine tautomer is very electron-deficient. I figured that the electron-deficiency of this carbon must be because it ...
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1answer
477 views

Stability of Nitromethane

Why is nitromethane not especially reactive? $\ce{NO2}$ is stable by itself, so why does it stay attached to $\ce{CH3}$?
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2answers
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Atomic orbitals: how is bond strength related to stability, energy, bond length?

I have a lot of confusion regarding atomic orbitals and I don't know if what I am having in mind is even correct or not. The bond dissociation energy of H-H is greater than that of Cl-Cl and as far ...
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Stability of cyclic radicals

How do we arrange the following in increasing order of stability? The answer given is: $5<3<1<2<4$ (numbering according to their order in the image). My Approach: I can figure that in ...
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3answers
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Why don’t all objects melt and liquefy when heated sufficiently?

Certain objects such as metals, glass, plastic, sugar etc. melt when heated to a certain temperature but other materials such as a piece of wood, paper, a piece of rock etc. do not. Why is that?
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1answer
510 views

Which is more stable chemically: DNA or peptide

Assuming enzyme-free environment, and the DNA and peptide are lyophillized, and then stored in vials under the same conditions (temperature and humidity). On average, which would be more chemically ...
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2answers
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What makes heat resistant proteins heat resistant?

We were doing the chapter Biomolecules in class the other day, and a doubt popped up once we reached the section on proteins. We were taught that the stuff that keeps proteins together are: Ionic ...
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Explaining The Different Order of Stability for singlet and triplet carbenes

Consider the following singlet carbenes: $\ce{CH2}$ , $\ce{CF2}$, $\ce{CCl2}$ The order of stability expected considering back bonding is; $\ce{CH2}$ < $\ce{CCl2}$ < $\ce{CF2}$ However the ...
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Why is cyclopropane planar?

What would cyclopropane look like if it weren't planar? How and why does non-planar cyclopropane have higher torsional strain than planar cyclopropane? can you please show me visually via image that ...
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1answer
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Thermal stability of interhalogen compounds

I am striving over the question that what would be the stability order of the following interhalogen compounds : $\ce{ClF3, BrF3}$ and $\ce{IF3}$. One probable answer I got is that stability of ...
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1answer
550 views

Could one synthesise unsubstituted “cyclohexa-1,3,5-triene”?

Is the cyclohexa-1,3,5-triene (non-aromatic benzene) possible to make or will it destabilize (or should I say stabilize?) into benzene? Cyclohexa-1,3,5-triene is alternative name of benzene better ...
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2answers
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Why is the cis isomer of 1,3-dimethylcyclobutane more stable than the trans isomer?

I expect there to be more steric repulsions between the two methyl groups if they are on the same face as each other. Why is this not the case?
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1answer
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Conversion of isonitrile (isocyanide) group into cyanide group?

In an isonitrile (isocyanide) group, the carbon atom has a negative charge (I know that this is due to the lone pair of electrons) instead of the nitrogen atom, but in my point of view, this seems a ...
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1answer
411 views

Is a sequence of two Wagner-Meerwein rearrangements possible?

We've just studied about the Wagner-Meerwein rearrangement in carbocations. Our teacher told us that it occurs in order to stabilize the carbocation intermediate. Knowing the carbocation stability ...
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0answers
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Why does octet bring stability? [duplicate]

After studying chemical bonding I am stuck at a question that is fundamental to my understanding of chemistry: What is it that makes 8 electrons in the valence shell stable? I googled it and got ...
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3answers
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Which conformations of 2,3-dimethylbutane are more stable?

I am not sure what the proper arrangement of these conformations are from least to most stable. I got the wrong answer, but my thinking was this: First, I thought that because 2 and 4 are in eclipsed ...
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1answer
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Why is benzenediazonium fluoroborate water insoluble and stable at room temperature?

Benzenediazonium fluoroborate is water insoluble and stable at room temperature. Why is this salt, water insoluble? Also I am told that benzenediazonium salts are stable only at low temperature(<5°...
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1answer
247 views

stability of complexes

Amongst the following the most stable complex is: A) $\ce{[Fe(H2O)6]^3+}$ B) $\ce{[Fe(NH3)6]^3+}$ C) $\ce{[Fe(C2O4)3]^3-}$ D) $\ce{[FeCl6]^3-}$ I know that the answer should be $\...
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2answers
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sp2 hybridized carbon versus sp3 hybridized silicon

Carbon's most commonly found allotrope is graphite/soot/fullerene/carbon nanotubes which are all $\mathrm{sp^2}$ hybridized forms of it, while silicon being its first periodic twin is mostly found in ...
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1answer
501 views

Reactivity and transport safety of substituted methyl benzoates

This was a practice question from an MCAT book whose answer I didn't really understand: The normal reactivity of methyl benzoate is affected by the presence of certain substituents. Which of the ...
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1answer
2k views

What factors affect the chemical stability of a compound? [closed]

My question is essentially about the factors that make certain atoms in certain compounds leave the compound they are currently in in order to bond with another atom/compound. For example, I've been ...
0
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1answer
209 views

Can the molecule CH2(ONa)2 be stable?

While studying about Cannizzaro reaction, it came to my mind as a wild thought what if this HCH(ONa)(ONa) molecule could pop out in some step of this reaction (not giving much details about how I ...
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2answers
513 views

Liquids that keeps the lowest temperature for the longer time after being frozen

I am working on a personal project, however I know nothing about chemistry and I would like to ask you guys for a quick question. I need to use a liquid for my project, which after being put into a ...
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1answer
249 views

Which base pair is more stable, U:G or I:C?

As a result of damage (usually deamination), DNA will sometimes contain uracil and inosine bases. I am trying to determine which unnatural base pairing combo would be more stable: uracil paired with ...
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1answer
357 views

Why don't we see these lanthanide species?

For most lanthanide metals$^{[1]}$, the stable oxidation state is III. The general electronic structure$^{[2]}$ is $$\ce{[Xe] 4f^{0}^{-14} 5s^2 5p^6 5d^{0}^{-1} 6s^2}.$$ Elements that have the d-...
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0answers
309 views

Predominance of III oxidation state for lanthanides [closed]

For most lanthanide metals, the stable oxidation state is III [*]. The general electronic structure is $$\ce{[Xe] 4f^{0}^{-14} 5s^2 5p^6 5d^{0}^{-1} 6s^2}\ \ [**].$$ Elements that have the d-electron ...
6
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1answer
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Why is cyclopentadiene more stable than its aromatic counterpart cyclopentadienyl anion?

What will be the order of stability? The answer key says that the stability order is: cyclopentadiene > cyclopentadienyl anion > cyclopentadiene cation According the me it should be: ...
2
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1answer
2k 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 ...
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1answer
4k 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
745 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
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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
737 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, ...
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1answer
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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 ...
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1answer
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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
148 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
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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 ...
0
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1answer
5k 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
524 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
725 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
454 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
831 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
483 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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