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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Why are palladium and platinum carbonyls unstable at room temperature?

By palladium and platinum carbonyls, I mean the mononuclear, homoleptic, charge-neutral, binary carbonyl complexes of the form $\ce{M(CO)_n}$ and not any heteroleptic complexes like $\ce{Pd(CO)(PPh3)3}...
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Were gold(II) complexes synthesized for the first time in 2017?

Recently in the Google news feed, I discovered this news: Gold stabilized in very rare oxidation state +II Missing golden link found: Divalent gold complex isolated for the first time in a ...
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319 views

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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606 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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179 views

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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62 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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127 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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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 ...
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38 views

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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196 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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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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30 views

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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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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90 views

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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77 views

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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241 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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838 views

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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58 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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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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168 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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236 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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104 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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671 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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119 views

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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134 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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1k views

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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162 views

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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106 views

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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Is the reaction of anhydrous aluminium(III) chloride and anhydrous ethanol reversible?

I'm planning an experiment that I'll do in silico in the near future, and one of the steps involves the extraction of the $\ce{AlCl3 · C2H5OH}$ adduct without any water in it. Can the ethanol be ...
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19 views

Stability order of chelate complexes of nickel and iron

Which stability order is correct? $\ce{[Ni(en)2]^2+} > \ce{[Ni(dmg)2]}$ $\ce{[Fe(edta)]^2-} > \ce{[Fe(en)3]^3+}$ In the first case I think the stability depends upon the strength ...
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40 views

Classic/killer/easy application for the deuterium kinetic isotope effect?

I'm a physicist. While visiting someone's o-chem class I learned about the existence of the deuterium kinetic isotope effect. This seems like an extremely sweet example of zero-point energy, and I ...
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54 views

Maximum lifetime of plastic on earth

[EDITED] If humans disappeared today, and aliens visited in the future, for how long would plastic or other "obviously" non-natural polymers be detectable on the planet, using known or plausible ...
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41 views

Does 2,2-dimethylpropan-1-ol give a positive Lucas test?

I learnt that the Lucas test involves the formation of a carbocation and it gives a positive test based on the stability of the carbocation formed, and hence primary alcohols do not show turbidity (...
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69 views

Stability of Cycloalkyl Carbocations

What is the order of stability of the cycloalkyl carbocations? I think the stability should increase as we move from cyclopropyl carbocation to cyclohexyl carbocation, since the angle strain is ...
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47 views

Determination of the most acidic hydrogen in an organic compound

Identify the most acidic hydrogen in the compound below: Can someone please explain why is $\ce{H^\mathrm{a}}$ in the compound below more acidic than $\ce{H^\mathrm{b}}$? This is what is ...
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35 views

What are the total amount of resonance structures for these two cations and which is the most stable cation?

Please see the following two cations. I have proposed the following resonance structures. Please let me know if I have missed something. Thank you.
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679 views

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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215 views

What is the stability order for these octahydrobiphenylene structures?

According to me most stable is Z because it has maximum alpha hydrogen, Between X and Y both have same alpha hydrogen, but X has conjugation. So it is more stable than Y. So Order is Z>X>Y. Is my ...
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54 views

Do amides oxidize to double-bonds?

Do amides from primary or secondary amines ever oxidize to a double-bond on the nitrogen? For example, like from an $\mathrm{R \bbox[yellow]{\color{red}{-}}(NH)-(C=O)-R'}$ to an $\mathrm{ R \bbox[...
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154 views

Reversed trends in stability of transition metal ions with respect to oxidation state

Why is titanium more stable with a lower oxidation state, but vanadium more stable with a larger oxidation state? More specifically, why is $\ce{Ti^{+}}$ more stable than $\ce{Ti^{3+}}$, but $\ce{V^{...
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370 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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194 views

Inductive effect in cyclic compounds vs open-chained compounds

Consider the two carbocations. Which one is more stable? I think it should be the open-chained one as it has 2 more H atoms than the cyclic one, so polarity will be greater; but I suspect that there ...
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48 views

Functionalizing CTAC stabilized nanoparticles

I am working on functionalizing silver-gold bimetallic nanoparticles. My nanoparticles are stabilized by CTAC(cetyltrimethylammonium chloride).The most articles which I found, are about the ...
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261 views

Which carbocation is more stable?

Which one of Tropylium cation (cycloheptatrienyl carbocation) and Cyclopropylmethyl carbocation is more stable? Several references present opposing views on this topic, hence the confusion. Reasons ...
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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 ...
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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 ...