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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Stability comparison between Acetylene/Ethyne (C2H2) and Nitrogen Gas (N2)

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 ...
Maddy's user avatar
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Is [Hg(SCN)4]2- more stable than [Fe(SCN)]2+?

My textbook explains Le Chatelier’s principle with: Fe3+(aq) + SCN-(aq) ⇌ [Fe(SCN)]2+(aq) It states that on adding Hg2+ in the above solution in equilibrium, the equilibrium shifts towards the left. ...
Hdje's user avatar
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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-...
mechanist's user avatar
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Is This compound stable at room temperature?

This compound is planar conjugated and has 8 pi electrons on its periphery so it can be anti aromatic but if we polarize the pi bond at the bottom of the right ring the left ring will become aromatic ...
shur's user avatar
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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 ...
akhmeteli's user avatar
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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 ...
Alex I's user avatar
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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 ...
akhmeteli's user avatar
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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:...
NFA's user avatar
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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 ...
Dannis's user avatar
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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 ...
Shira's user avatar
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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 ...
Kavin Ishwaran's user avatar
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1 answer
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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, ...
Freeby Freeby's user avatar
3 votes
1 answer
125 views

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 ...
raptorlane's user avatar
5 votes
1 answer
228 views

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 ...
Cyclopropanol's user avatar
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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?
MasterMind's user avatar
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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 ...
big_yoshi's user avatar
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1 answer
130 views

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 ...
InactionBreedsMediocrity's user avatar
3 votes
2 answers
254 views

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 $\pu{800°C}$ ...
Spinnel's user avatar
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1 answer
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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 ...
user3700272's user avatar
1 vote
2 answers
147 views

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 ...
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NIST SRMs: Determination of the Validity Period

The National Institute of Standards and Technology (NIST) produces Standard Reference Materials (SRMs) of basically anything. That also means that things like peanut butter are among those SRMs. SRMs ...
Kreuvf's user avatar
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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 ...
AltercatingCurrent's user avatar
6 votes
1 answer
308 views

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 ...
Proscionexium's user avatar
2 votes
1 answer
123 views

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 ...
JinSnow's user avatar
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1 answer
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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 ...
Isteak Ahamed Imon's user avatar
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Why is anhydrous trans-Bis(glycinato)copper(II) more stable than it's cis isomer?

As is shown in Ref.1, the trans isomer is much more stable, at least at molecular level. Based on the crystal structural data from Ref.2 and atomic radii of O and N from wikipedia and some little ...
RTChou's user avatar
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1 answer
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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 ...
Sudarshan Kulkarni's user avatar
2 votes
0 answers
87 views

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 ...
Mithun M R's user avatar
3 votes
2 answers
396 views

Stability of hexazine

I read about a hypothetical compound called hexazine on Wikenigma. It's a 6-membered ring all of whose atoms are nitrogen and they form alternate single and double bonds just similar to benzene. But ...
Proscionexium's user avatar
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1 answer
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Is there an international standard for rating the danger of chemical elements?

I'm writing a small little tool (something like an interactive periodic table) and I wanted a good "guesstimate" of the danger of certain elements, to visualize across said table. I could go ...
Mister SirCode's user avatar
5 votes
1 answer
482 views

Why is water present in "pure" nitric acid and RFNA and WFNA?

Various types of nitric acid have been used in rocket fuels as oxidisers (RFNA is red fuming nitric acid, WFNA is white fuming nitric acid) as they are often hypergolic with a wide variety of fuels. ...
matt_black's user avatar
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2 answers
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Are mixtures of finely ground solid fertilizer compounds stable? [closed]

If I had a combination of the following as finely ground powders, would it be relatively stable, or would they react to form other compounds? Sodium Nitrate Ammonium Nitrate Calcium Nitrate Potassium ...
airplantlover's user avatar
1 vote
1 answer
969 views

Why is the reaction rate of tert-butyl chloride solvolysis faster in 80% water/20% acetone, than in 70% water/30% acetone?

The solvent is polar protic, so the mechanism is SN1. However, I don't understand how the composition of water and acetone in the solvent affects the reaction rate.
songgio123's user avatar
1 vote
0 answers
703 views

What happens when iron(III) chloride is dissolved in ethanol?

I dissolved $\pu{25 mmol}$ $\ce{FeCl3*6H2O}$ in $\pu{25 ml}$ ethanol and got a clear ethanol solution of $\ce{FeCl3}$ 4 days ago. And I keep it in a drawer from light these four days. However, when I ...
Fikry TAN's user avatar
4 votes
1 answer
764 views

Does germanium(IV) chloride have to be handled under inert atmosphere?

I am finding conflicting information on the proper handling of germanium(IV) chloride. Is the liquid air/moisture sensitive? Does $\ce{GeCl4}$ have to be handled in a glove box?
seisenberg19's user avatar
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Why does chlorine displace bromide

Found that chlorine will displace bromide, and iodide from their ion forms. According to my textbooks, this is because chlorine is more electronegative than bromine and iodine. However, the chloride ...
TheRavenSpectre's user avatar
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1 answer
120 views

Store Palladium Chloride in Solution

I have one gram of palladium chloride ($\ce{PdCl2}$) and I want to use very small quantities of it, in milligrams somewhere. It is not possible for me to get my hands on a scale that can measure that ...
Umer's user avatar
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Which Group 16 elements form stable dihalides?

My textbook says that "except oxygen, all elements of group 16 form dichlorides and dibromides", while other sources quote that only Oxygen and Sulphur form dihalides and dibromides. Whereas,...
Chem1234's user avatar
1 vote
1 answer
181 views

Why and how do aqueous silica systems precipitate and can its occurrence be mitigated by quantifying its speciation correctly?

Background/Context: For context, I have been doing a lot of work on experimental systems in geopolymer chemistry lately with a focus on "activator" solutions which are essentially mixtures ...
Hendrix13's user avatar
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1 vote
1 answer
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Why the electronic configuration of samarium is ending with 4f⁶6s²

What is coming in my mind is that 4f^7 6s^1 should be more stable as it allows two orbitals to be half filled rather than 4f^6 6s^2 in which only one orbital is completely filled....can someone please ...
Ved's user avatar
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1 answer
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What makes a compound high or low energy and why does that relate to reactivity? [closed]

After reading about thermodynamic stability, it now makes sense to me how the enthalpy of a reaction relates to the thermodynamic stability of a compound. However, when looking for a clear way to ...
Meet Nair's user avatar
2 votes
1 answer
134 views

How specific is the exception of negative charge location (orbital vs atom) for determining stability of conjugate base?

Chapter 3 Acid-base reactions in Klein's Organic Chemistry As a Second Language explains an exception to the typical order of important factors for determining how stable a negative charge on a ...
TNF's user avatar
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Stability comparison of europium(II) and ytterbium(II) ions

“Which one of the lanthanoids given below are most stable in divalent form?” This question was asked in JEE Main 2022 (Indian entrance test for engineering). Now the question had both $\ce{Eu^2+}$ and ...
Nam347 7's user avatar
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42 views

Why isn't formyl chloride stable? [duplicate]

I am currently studying methods of synthesising ketones and aldehydes and one of the methods is Friedel-Crafts acylation. However, my teacher told our class that we can't use this to make benzaldehyde ...
math and physics forever's user avatar
3 votes
3 answers
208 views

Comparing reactivity of 3-bromocyclohexa-1,4-diene and 5-bromocyclohexa-1,3-diene towards SN1 reaction

Compare reactivity of 3-bromocyclohexa-1,4-diene (P) and 5-bromocyclohexa-1,3-diene (Q) towards $\mathrm{S_N1}$ reaction. My teacher claims that the reactivity of P is more than that of Q. He ...
ultralegend5385's user avatar
1 vote
0 answers
104 views

Reactivity vs Stability: Chlorine Trifluoride

Chlorine trifluoride shows up on many pop science content, which is how I learned about it just today, as an incredibly reactive compound capable of oxidizing seemingly incombustible substances (glass,...
BatWannaBe's user avatar
4 votes
1 answer
248 views

Has tellurium(II) iodide been properly characterized ever?

According to Wikipedia, tellurium tetraiodide decomposes on heating: $$\ce{TeI4 ->[\Delta] TeI2 + I2}$$ However, the reaction is somewhat wrong as according to this 2008 paper: Solid tellurium ...
Nilay Ghosh's user avatar
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What is the most stable cycloalkene? [closed]

I'm looking specifically at cyclopentene and cyclohexene. Supposedly, greater instability would lead to a more exothermic enthalpy of combustion. However, based on my data, cyclopentene is more ...
Evan's user avatar
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2 votes
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Has a fully methylated pentagonal dodecahedrane been synthesized or at least attempted? If not, is there some reason it could not exist?

I first came across dodecahedrane in comments below What dodecahedral molecule is Linus Pauling likely holding in this photograph? Does it have 40 carbon atoms? Wikipedia's Dodecahedrane; Derivatives; ...
uhoh's user avatar
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Dominance of electronic factors in cupric ion

I know that Cu+ ( cuprous ) ion is less stable than Cu²+ ( cupric ) ion . There are some reasons explaining this by high hydration enthalpies and low ionization enthalpies . Even though , these ...
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