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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Bredt's rule applied to fused bicyclic systems

Ultimate question: Is Bredt's rule equally valid for fused bicyclic system (no bridgehead alkenes without a ring 8 carbons or more), but for other reasons (historical?) it is only defined as applying ...
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729 views

Stability of cyclic isomers of C6H12

I was given the problem to arrange all cyclic isomers of $\ce{C6H12}$ from the lowest to the highest heat of combustion. I found twelve isomers and quickly realised that cyclohexane is the most stable ...
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pKa of different sites of butanone

From what I can tell, deprotonation of the central hydrogen leads to the more thermodynamically stable product (most substituted double bond. i.e. most stabilization by hyperconjugation). Therefore, ...
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What is tetrasulfur like? Why is there so little experimental information about it?

Phys.org's How sulfur helped make Earth habitable before the rise of oxygen says Mapping the bonds and vibrational modes of molecules containing sulfur isotopes is helping to shed light on the ...
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Stability of carbocation

While comparing the stability, as the $\ce{CH3}$ group is electron donating, the first structure should be more stable due to this reason. But apparently the second one is more stable. Is there ...
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105 views

Wade's rules applied to metallic elements

There are many examples of metallic clusters that distort from the structure predicted by Wade's rules to a more 'spherical', closo-like arrangement. For example, $\ce{Bi8^2+}$ is a square antiprism ...
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323 views

Stability of extended enolates

I'd expect an extended enolate to be more stable than a normal enolate, when both can form, but my textbook suggests otherwise. What is the stability of an extended enolate compared with a normal ...
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135 views

Where is my antimony going?

I work in a trace metals laboratory operating an ICP-OES. I've been having some trouble with the recovery of antimony in a weak $\ce{HCl}$ solution post-digestion. The antimony is part of a mix of ...
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1answer
45k 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 ...
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Why is PbI₄ not composed of lead(II), iodide and triiodide?

$\ce{Pb^4+}$ is reduced by $\ce{I-},$ so $\ce{PbI4}$ cannot exist with $\ce{Pb}$ in $+4$ oxidation state. But if I replace three $\ce{I-}$ with $\ce{I3-},$ then we can have $\ce{Pb^2+}$ similar to $\...
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Is there an enolate equivalent for enamines?

I'm learning that enolates are stronger than enamines are stronger than enols in terms of general nucleophilicity. Makes sense. But what I can't find any explanation for online is why the trend ...
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Is N--O--N known to exist?

Commonly, the empirical formula $\ce{N2O}$ refers to the molecule with structure $\ce{N\bond{~--}N\bond{~-}O}$. Is the isomer $\ce{N-O-N}$ known to exist? I'm guessing it is significantly less stable ...
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74 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 ...
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Why are sulfoxides usually stable as ylides (S charged positively and O negatively)? What's the BDE for S-O?

I can't find any info on BDE for singularly bonded S to oxygen. Moreover, I'd like to understand, why is it quite usual to find sulfoxides structure written with charge separation?
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Preferred radical attack on a polyester

My question concerns the relative stability of a radical next to an ester oxygen compared to a radical next to an ester carbonyl carbon. The stabilizing effect of the electron pairs of ether oxygen ...
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77 views

Why isn't protium nucleus considered most stable nucleus?

My chemistry teacher told me that $\ce{^{56}Fe}$ is the most stable nucleus because of the highest binding energy per nucleon. But if we consider a protium nucleus, it has only 1 proton so there is no ...
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On the stability of methyl mercury

Question: Given that $\ce{Zn, Hg}$ are in the same group, how to explain that $\ce{Hg(CH3)}$ is stable but $\ce{Zn(CH3)}$ is unstable and $\ce{Hg(CH3)Cl}$ is stable? $\ce{Hg(CH3)}$ seems to have an ...
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363 views

Which is more stable: isobutylene or cis-2‐butene?

How do you compare which is more stable without using the heat of hydrogenation or combustion or any other numeric factual value: $\ce{(CH3)2-C=CH2}$ or $\ce{CH3-CH=CH-CH3}$ (cis)?
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Chugaev and Selenoxide Elimination giving different products

In class we are going over intramolecular elimination. In this question I will provide two similar reactants that provide a different mixture of products. The chugaev elimination gives a 50/50 ...
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541 views

Could Be2- exist?

I understand that Be2 cannot exist, since it has as many electrons in the antibonding as in the bonding orbitals. But it seems to me that since the next electron would go into the πu orbital, which ...
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Carbon atoms which carbocation and carboanion are BOTH less stable then arene/vinyl

I'm trying to come up with a compound class in which iodine atom would be a bad leaving group both whether it leaves or takes charge with it (I know that $\ce{I^+}$ on its own would be horrible ...
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357 views

Acidity of ethers vs alkanes

I wonder if ethers are more or less acidic at the alpha position than alkanes ($\mathrm{p}K_\mathrm{a} \approx 50$). I'm not sure if the stabilising inductive effect from oxygen or the alpha effect (...
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Which enolate of butanone is more stable?

Consider butanone (A) and its two possible enolates B & C. Which of the two enolates will be more stable? B because of the more stable primary carbanion, or C because of more stable enolate (...
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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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How is the thermal stability of nitric acid related to its structure?

How is the thermal stability of nitric acid related to its planar structure? In textbooks it is written that nitric acid is unstable at room temperature and decomposes where $\ce{H2SO4}$ and $\ce{...
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64 views

What is the relation between strength of a base and the thermal stability of its salts?

In Concise Inorganic Chemistry, $5^{th}$ edition, by JD Lee, while discussing oxides and hydroxides of Group $2$ metals, it has been stated that: The increase in basic strength is illustrated by the ...
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115 views

Regarding stability and reactivity of m-xylene

I came across the following two details about m-xylene: m-Xylene is thermodynamically most stable compound among o-xylene, m-xylene, and p-xylene. m-Xylene is most reactive towards nitration and ...
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83 views

Does 2‐indanone form a stable hydrate?

Following up the question Formation of a stable hydrate. I understand that for cyclopropanone the change in hybridization is the reason for stabilization of hydrate since it relieves the angle strain. ...
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Why does more s-character stabilise Carbanions?

Since carbanions carry a negative charge, more the distribution of electron density, more is the stability. What does this have to do with more s character? Does the distribution of electron density ...
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86 views

Does mercury(II) cyanate exist?

Recently, I have answered a question "Comparing explosive properties of mercury(II) cyanate and mercury(II) fulminate" where stability of cyanate vs fulminate was discussed. While I was ...
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317 views

Why do alkyl substituents stabilize alkenes?

My textbook states that because $sp^2-sp^3$ bonds are stronger than $sp^3-sp^3$ bonds, alkenes are more stable than alkanes. The rule given is that bonds with more $s$ character are stronger. However,...
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631 views

How does cross-conjugation destabilizes a molecule?

Wikipedia article on ortho effect suggests that o-toluic acid is more acidic than benzoic acid. This fact is rationalized by suggesting that steric effect causes COOH group to "twist" out of ...
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240 views

Stability of the alkenyl and phenyl cations

One reason often cited for why alkenyl and phenyl halides do not undergo nucleophilic substitution by the $\ce {S_N1}$ mechanism is that the formation of the alkenyl and phenyl cations involve a ...
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481 views

Stability of methoxy-methyl and tropylium carbocations

Which is expected to be more stable: methoxy-methyl carbocation $(\ce{CH3-O-CH2+})$ or tropylium $(\ce{C7H7+})$ cation? I think because oxygen would donate its lone pair so there will be complete ...
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Comparing thermal stabilities of MgCl2 and BaCl2

I read that to compare thermal stabilities of ionic solids: if the solid has a monoatomic anion, we compare thermal stability on the basis of lattice energy which is inversely proportional to size. ...
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736 views

Why is Cr+ unstable?

We know that half-filled and fully filled orbitals are highly stable. In ground state $\ce{Cr}$ has a $\ce{3d^5\! 4s^1}$ configuration. Therefore, the elctronic configuration of $\ce{Cr+}$ should have ...
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126 views

Stability of Halide Salts of Different Metals

Between $\ce{EuCl3}$, $\ce{RuCl2}$, and $\ce{VCl}$, order in increasing stability. I don't know if this is a dumb question and if the answer is blatantly obvious, but I don't understand how to "...
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968 views

Inductive effect on stability of free radical

How does inductive effect affect the stability of free radical? I can't seem to understand whether the carbon with the odd electron is deficient or not. That is, whether a +I group, like alkyl, will ...
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Why do compounds form if overall energy of free ion increases according to CFT

According to crystal field theory, a free ion has certain energy and its energy increases when it is symmetrically surrounded by ligands. Now the degenerate d orbitals split into two new set of ...
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154 views

Properties of metallic hydrogen

Given the possibility that metallic hydrogen may have recently been produced, and the massive media bloviation that followed, I am curious about some of the "properties" that I heard from multiple ...
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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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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, ...
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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 ...
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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 ...
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If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium?

If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium? Can the same argument be applied to nitrous acid and nitrite ion in ...
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Is Oxide Anion more stable than O^+

O likes to be negative if charged at all. Most metal oxides are of the form $\ce{A^{x+} O^{2-}_{x/2}}$ (where $x$ is the magnitude of the positive charge and $\ce{A}$ is a metal.) Here, despite the $\...
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Is an emulsion of dish soap and vegetable oil stable?

If I fill a glass jar with water, vegetable oil, and dish soap, then mix it until the oil is completely emulsified, will the mixture stay emulsified indefinitely? Assuming the dish soap and oil are ...
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Which is more reactive in E1, benzyl or allyl

I'm don't know the english terminology for chemistry so sorry for probably butchering some terms. My question is, which of these is more reactive in an E1 reaction: The bottom two are the ...
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Hydrogen isotope effect on methyl shift

Consider this typical 1,2 methanide shift in a carbocation: Which isotopic form of methanide ($\ce{CH3, CD3, or CT3}$) would migrate from secondary carbocation to form more stable tertiary ...
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Cis-Trans Isomers Heat of Combustion

Consider the 4 cis-trans isomers for the above compound. In what way would the cis-trans isomers affect their heat of combustion. I think that if the substituents are on alternating sides of the ...