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.
556 questions
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Which tautomer of nitrous acid is more stable?
Context: While I was revising the mechanism of diazotisation by writing it down myself(without looking at my notes), I realized that there are $2$ possible structures for $\text{HNO}_2$, both of which ...
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Temperature of thermal dissociation of carbon monoxide?
I was reading a paper about CO2 splitting, which mentions limitations of high temperature approach:
NTP even in the presence of solid catalysts is not able itself to
effectively promote the CO2 to C +...
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β-Effect in vinylsilanes
I am reading about the β-silicon effect that stabilizes carbocation in the β-position [1, p. 672]:
The familiar hierarchy of carbocation stability—tertiary > secondary > primary—is due to the ...
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Comparing the acidic strengths of four substituted phenols (4-X-Ph-OH)
Compare the acidic strengths of 4-nitrophenol, 4-hydroxybenzaldehyde, 4-hydroxybenzenesulfonic acid, and 4-hydroxybenzoic acid:
In this problem, I was asked to determine the order of acidic strength, ...
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The Reason Behind the Order of Carbanion Stability: Tertiary, Secondary, Primary, and Methyl Anions
I'm trying to understand why carbanion stability follows this order:
tertiary carbanion (least stable) < secondary carbanion (moderate stability) < primary carbanion (more stable) < methyl ...
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Why is it hard to make red and black phosphorous in labs?
I was going through standard states of different elements and found that we take phosphorous as white. The reason was stated that its because its hard to make black and red phosphorous in labs. Why is ...
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Order of decarboxylation of compounds
Checking the carbanion stability, I get that (c) > (d) because NO₂ is a better -M group than -CN and the +I effect in (c) & (d) does not affect much as is weaker than -M. However in the first ...
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Why are orthonitrate ions not found in nature?
In general chemistry we often encounter $\ce{H3PO4}$, which got me wondering if I can replace the $\ce{P}$ in $\ce{H3PO4}$ with $\ce{N}$ giving us $\ce{H3NO4}$ , does such a compound exist?
Both ...
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why tricyclopropyl methyl carbocation the most stable carbocation [duplicate]
Triphenyl carbocation has 36 resonance structures, but Tropylium carbocation which has 7 structures is more stable than triphenyl carbocation and cyclopropyl methyl carbocation is more stable and as ...
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Comparing stability of acetate and formate with respect to inductive effect
According to my teacher, the order for +I effect is
$$\ce{-CH2-} > \ce{-NH^-} > \ce{-O^-} > \ce{-COO^-} > \ce{-R} > \ce{-H}.$$
So, $\ce{-COO^-}$ must have more pronounced +I effect ...
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What is the highest known temperature where micelles exist?
What are the two liquid phases involved in the formation of roughly spherical micelles at highest possible temperatures? What about a surfactant? At how high temperatures have micelles been observed ...
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Drug dosage determination using dynamical systems
I am a Mathematical Biology student, and recently I have read about various approaches, such as Ordinary Differential Equations (ODEs), used to determine the exact drug dosage and treatment sessions ...
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Is cyanomethanide more stable than 2‐oxoethanide?
Which carbanion is more stable?
$$\underset{(\textbf{a})}{\ce{H2\overset{-}{C}-CN}} \qquad \underset{(\textbf{b})}{\ce{H_2\overset{-}{C}-CHO}}$$
If we talk about the −M effect, $\ce{CN}$ is higher ...
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Stability order of xylenes [duplicate]
M-xylene is the most thermodynamically stable amongst the three isomers due to hyperconjugation. Can we comment on the stability order of the other two forms as well? If yes, what would be the order ...
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Identify the more acidic hydrogen in 1-(methylsulfanyl)propane-2-thione
This was a question that was asked in one of my exams, in which we had to confirm if the given order was correct or incorrect. The key says the given order is correct and the professor at my high ...
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I was told that Lithium and group 2 bicarbonates does not decompose on heating.Group 1 bicarbonates does decompose except lithium
But in some sources it was explained that stability of group 1 bicarbonates increases down the group.If it is true then how does lithium bicarbonate does not decompose ?.Can anyone please tell me ...
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what role does mesomeric effect and inductive effect play in stability of carbocations in presence of halogens
what should be the ideal explanation behind the order of stability of these three compounds?
Case-1
In these three examples the first two structures have a positive mesomeric effect and it is greater ...
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How predictable are the decomposition temperatures of trithiocarbonates?
How do the following parameters:
Ionic radius of a cation.
Oxidation number of a cation.
Noble metal cation vs alkali metal cation.
Something else that I may not know about.
affect the decomposition ...
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Stability of atomic/ionic quantum states in relation to the full octet rule
We have started our Chemistry Unit and the very first statement the teacher says is that
"All Atoms want to be stable. They achieve this by having a full valence shell, which they achieve by ...
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Synthesizing Cyclotetrazane from Hydrazine and Diazene?
Could cyclotetrazane — a compound with nitrogen atoms arranged in a square configuration — be synthesized? A hydrogen atom would be bonded to each vertex (nitrogen atom):
Could cyclotetrazane be made ...
user145192
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Stability of phenylic carbocations [closed]
Problem:
Structure (1) is more stable than structure (2).
My teacher stated that Structure (1) is more stable than Structure (2). I find this confusing. How can Structure (1) be more stable when ...
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Stability of atoms with 4 valence electrons [closed]
How do atoms with 4 valence electrons stabilize? Do they gain or lose 4 electrons?
This might be a bit of a stupid question, but I'm not sure and I can't find anything online.
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Stability of Nitro substituted phenylic anion
Which of the following is more stable:
What I found on internet is 2nd structure ( meta position ) is more stable. But -NO2 shows -I (inductive effect) and -M ( metameric effect ) so ortho must be ...
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Why is 1-ethylcyclohexene more stable than ethylidene cyclohexane?
Both compounds yield the same product, ethylcyclohexane, when hydrogenated. However,
1-ethylcyclohexene has lesser heat of hydrogenation than ethylidenecyclohexane, hence more stable. I want to know ...
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Why doesn't HBr show allylic substitution in presence of Peroxide?
HBr reacts with alkenes such as propene in the presence of Peroxide as per the Anti-Markovnikov rule. This is an addition reaction, forming 1-bromopropane as the major product.
This happens due to the ...
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Stability comparison between Acetylene/Ethyne (C2H2) and Nitrogen Gas (N2) [closed]
N≡N is more stable than H2N—NH2 (hydrazine)
But
HC≡CH is less stable than H3C—CH3
Why is it so? Even though the size of the corresponding compounds and hybridization is the same?
(Usually ethane is ...
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Can a carbocation ever be more stable than a neutral molecule?
The question is about finding the most stable molecule or species. Now my thought process was that cyclopropenylidene(1) was a carbene so would be unstable even though it is aromatic. Cyclopenta-1,3-...
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Is pentalene stable at room temperature?
Pentalene is planar, conjugated and has 8 π-electrons on its periphery, so it can be anti-aromatic. But if we polarize either of the π-bonds adjacent to the central C−C bond, the other ring will ...
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How to chemically remove niobium from boron carbide?
Previously I asked about chemical removal of CaO from boron carbide. I keep considering some refractory materials for use as sacrificial ones, so now I wonder if and how a layer of niobium (about 1.5 ...
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Rule for which heterocycles are stable?
In medicinal chemistry, is there a rule for which aromatic heterocycles are stable?
I've heard that heterocycles with 3+ adjacent nitrogens for example are unstable. However looking in ChEMBL at the ...
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How to chemically remove CaO from boron carbide?
Previously I asked (How to remove graphite substrate of boron carbide coating?) how to chemically remove a thick layer of graphite from a thin layer of boron carbide. It turned out that was a hard ...
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Metal hydrolysis and equilbrium constants from stability constants
Problem: I want to create minimum solubility plots for a series of metal hydrolysis species against pH (below). But I cannot reconcile literature stability constants and equilibrium constants.
Context:...
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Which is more stable, a secondary allylic carbanion or a primary allylic carbanion?
I came across this picture in a polymer chemistry course, specifically on anionic polymerization of conjugated dienes (butadiene).
I dont understand why the secondary carbanion is more stable. Based ...
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Stability of H3MnO4, H2MnO4, HMnO4
I cannot seek out the reason why while $\ce{H3PO4}$ (phosphorus oxidation +5) is relatively stable and obtainable but $\ce{H3MnO4}$ (the same oxidation state +5) is rarely mentioned and perhaps ...
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How ring expansion is possible here?
Recently I have came across this question.
I went with the 3rd option as ring expansion cannot occur due to the formed stable 3 degree carbocation. But the answer key claims 4th option. How can ...
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Non-octet structures of stable nitrogen compounds
A question in my exercise book demonstrates that nitrogen cannot form non-octet structures since the most common examples — nitrogen dioxide and nitrogen monoxide — are unstable/reactive. For example, ...
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Are there LCMS compatible buffer systems available for the high pH range 12-14?
I want to perform chemical stability studies for different pH Values. To achieve pH Values from 1 to 6 I can prepare solutions with trifluoric acid and formic acid and ammonium formate and acetate. I ...
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Selective formation of enolates
I saw the following reaction on Modern methods of Organic Synthesis by Carruthers. The reaction is about the selective alkylation of trimethylsilyl enolates, and is shown below.
However, I have some ...
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What is that substance coming from tractor tire?
I have old tractor with Bridgestone tires. When I press a clean white tissue against the tire, a black spot show on the tissue. Is that substance carbon black and it’s harmful to soil?
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Which methoxy- and nitro-substituted azulene has the lower ground state energy?
My contention is that the first azulene structure, with the nitro group on the aromatic cyclopentene ring has a lower ground state energy, as the negative charge can not only resonate into the nitro ...
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Is it possible to have multiple nitrogen atoms bonded to one carbon atom?
So I was wondering, if we replaced two of the hydrogens in methane with amine groups, would it be a stable compound? What about for R groups of varying size?
Similarly, if I tried to make a compound ...
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Why is silver(I) phosphate so unexpectedly thermally stable?
Silver(I) oxide is completely decomposed in air already at $\pu{300 °C}.$
Formulate the decomposition reaction and the corresponding mass action expression.
$\ce{Ag3PO4}$ can be melted at $\pu{800°C}$ ...
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Why are p orbitals most important for stability? [closed]
Is there nice way to see/show/derive why p orbitals are so important for stability? Or asked differently: Why are elements with filled p orbitals on the right side of the periodic table? Why aren't ...
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Organic solvents distillation for purification
I've realised that the majority of the solvent that we use in my lab are contaminated with grease (peaks at 1.26 and 0.86 ppm in $^1H$ NMR in $CDCl_3$), since they come in plastic containers (I guess ...
user78790
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Does resonance stablization of carbocation increase ease of $\ce{S_N1}$ reaction or decrease it due to delocalization?
(A)
(B)
In both of the cases when a nucleophile approaches for $\ce{S_N1}$ reaction a carbocation is formed in place of $\ce{Cl}$ atom. I know that the rate of $\ce{S_N1}$ increases with increase in ...
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Stability of beryllium isotopes
I have been reading about isotopes and their abundance on Wikipedia. It states that lithium has 2 stable isotopes, beryllium has 1 stable isotope (monoisotopic and mononuclidic) and boron has 2 stable ...
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How long can a silicone and white spirit solution be stored without hardening?
I’ve heard that some people use a mixture of silicone and white spirit to waterproof their gear.
How long this solution can be stored without hardening if it is stored in a closed hermetic bottle?
If ...
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Stability of benzyl free radical hyperconjugated with a methyl group
In this picture, which one is more stable?
My teacher says the second one as it has 4 alpha-Hydrogen whereas in the first picture the free-radical carbon has only 1 alpha-Hydrogen. That's why second ...
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Stability comparison between tropylium, cyclopropylmethylium and dicyclopropylmethylium cations
Write the correct stability order of the following compounds:
I don't have any concern with estimating stability of (1), only (2), (3) and (4). Our teacher said that unless the carbocation has three ...
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Stability of different tautomers of vitamin C
Above all four tautomers represent Vitamin C (Ascorbic acid)
So here are some basic rules that I learnt.
1.Usually keto form is more stable due to bond enthalpy considerations
2.Enol form is stable if ...
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