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.

Filter by
Sorted by
Tagged with
-1
votes
1answer
37 views

Oxidation state of phosphorus in trialkylphosphine [closed]

Oxidation state of phosphorus in phosphine, $\ce{PH3},$ is $-3.$ $\ce{P-C}$ bonds are less polarised, i.e. almost purely covalent. In this concern, what is the oxidation state of a trialkylphosphine, ...
-1
votes
2answers
47 views

Stability of F- Cl- Br- I-? In aqueous state [closed]

If we talk about hydrolysis F- will be more heavily hydrolysed so it should be more stable in aqueous state. But I know that HI is a stronger acid than HF. So the stability of conjugate acid ie I- ...
0
votes
1answer
30 views

Why are bonded ions more stable than separate ions? [closed]

I was reading on the Born-Haber cycle when I encountered a problem. The textbook seemed to suggest that since energy must be supplied to separate an ionic compound into it's composite ions, then the ...
3
votes
3answers
189 views

Stability of α-chlorocarbocations

I'm trying to compare the relative stability of two carbocations: $$\ce{CH3-\overset{+}{C}H-Cl}\quad\text{vs}\quad\ce{CH3-\overset{+}{C}H2}$$ Does the $\ce{Cl}$ exert a +M effect to stabilisethe ...
4
votes
1answer
64 views

Newman projections: how to tell which groups are bulkiest to determine what is the most stable conformation?

The scenario Let's say we have a molecule where in the Newman projection the front carbon has a hydrogen, methyl and an ethyl, and in the back carbon there's a hydrogen, something like a S, Cl or Br (...
1
vote
1answer
196 views

Stability of CI4 and PbI4

I have read in my textbook that $\ce{CI4}$ is more stable than $\ce{PbI4}$ due to inert pair effect. But shouldn't we also consider the effect of steric repulsions? In $\ce{CI4}$, four large iodine ...
2
votes
0answers
14 views

Get fractional coordinates from special Wyckoff positions (IUCr)

I'm trying to get the fractional coordinates for Mo and S, for MoS$_2$-2H, where 2H means the phase. MoS$_2$-2H is a bilayer, in which each layer is separated from each other by Van der Waals forces. ...
-1
votes
2answers
55 views

Ortho effect in cyclohexane

Compare the acidities and basicities of the compounds in the first and second row respectively. In aromatic compounds the methyl group would cause an "ortho" effect. Here we don't have an aromatic ...
-2
votes
1answer
45 views

Energy lost due to stability [closed]

We used to say that when an atom is stable it is in its minimum energy state.Every shell has its fixed energy. So from where does the energy come which is lost by an atom to achieve stability. Do ...
0
votes
0answers
28 views

Stability of Peroxynitric Acid in cold temperature

I have a question about the stability of Peroxynitric Acid i.e. $\ce{HO2NO2}$ at cold temperature. I know that it becomes stable when temperature decreases, but what is the specific reason for it? I ...
1
vote
1answer
97 views

What does it actually mean by stability of an atom

There are several rules related to stability of an atom, like octet rule, half filled or fully filled d orbital etc. But none of them (at my best knowledge) does not explain why an atom is stable when ...
1
vote
0answers
48 views

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 ...
2
votes
2answers
82 views

Why is hofmann product prefered here?

In the following reaction, Hofmann elimination is preferred. This reaction takes place by E1 mechanism. I thought the Zaitsev product would be major due to 1 extra hyperconjugating structure. In the ...
0
votes
0answers
26 views

What explains the stability of aromatic compounds? [duplicate]

We are taught in High school that aromatic compounds are highly stable. Why is that true? Also, Why are Antiaromatic compounds highly unstable? Aromatic compounds have 4n+2 (n is a whole number) ...
1
vote
0answers
66 views

Stability order of p-quinone, o-quinone and diphenoquinone

Question Determine stability order: Answer Thoughts I found this question quite tricky and confusing. According to my concepts and logic 3 should be non-aromatic, while 1 and 2 are antiaromatic. ...
0
votes
2answers
66 views

Which resonance structure would be favorably contributed to the actual structure?

Total number of pairs of resonating structure in which second is more favorable than first: I know (d) and (e) have second structure more stable. (f) has both same. According me to, (a) and (c) ...
0
votes
1answer
48 views

Para effects on substituents in aromatic compounds

I wanted to know how to compare the following compounds on basis of acidic strength. I have to find the acidic strength of following compounds with $\mathrm{X}=\ce{CH3, \ OCH3,}$ and $\ce{NO2}$. For ...
2
votes
0answers
51 views

Are all ions stable? [closed]

My science teacher says that all ions are stable, which seems wrong to me. For example $\ce{He^{-1}}$ is an unstable ion of helium, and although it might not exist in the real world, it is still ...
3
votes
0answers
39 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 ...
-2
votes
1answer
51 views

Why do stable compounds have a lower heat of combustion?

My brain somehow doesn't accept that more stable compounds require have less enthalpy. Isn't it like, if a compound is stable, it requires more energy to break the bonds because the compound doesn't ...
0
votes
3answers
62 views

Odd looking carbocation stability order [duplicate]

I am studying introductory organic chemistry, suddenly this one started looking odd, The carbocation stability for three compounds as given by my book is shown below, Let me call those as ...
11
votes
1answer
123 views

The Evasive Ether: Existence of diethynyl ether?

I tried to find online whether the compound diethynyl ether, $\ce{HC#COC#CH}$, exists in a stable state at STP, mainly out of curiosity, but also because it would be interesting to study the ...
-3
votes
1answer
64 views

Why is the chlorine ion more stable than the chlorine atom? [closed]

In heterolytic cleavage, for instance, $\ce{NaCl}$ breaks in two fragments $\ce{Na+}$ and $\ce{Cl-}$. If chlorine is fully filled because it takes one electron from sodium, then why does chlorine make ...
0
votes
1answer
35 views

Acidity order of organic compouds

Here is the question: We have to find the order of their acidity. Here is my thought process: We check the acidity order by finding which conjugate base is more stable. Thus we remove $\ce{H+}$ from ...
3
votes
1answer
57 views

Quantitative measurement of ring strain

While looking for data about ring strain in cycloalkanes, I came across two types of data: Ring strain per methylene group (let's denote this quantity by X): The difference between heat of combustion ...
4
votes
1answer
198 views

Heats of combustion of cycloalkane homologues

Heat of combustion increases as the number of carbons increases, but on comparing ethyl cyclopentane, ethyl cyclohexane, andethyl cycloheptane, shouldn't you consider ring stability too? In that ...
-2
votes
1answer
300 views

What is the trend of thermal stability of group 1 oxides?

The thermal stability of most compounds of Group 1 elememts (hydroxides, carbonates, nitrates) increases down the group due to decrement in charge density of the cation. Now, according to one of my ...
1
vote
1answer
157 views

How to figure out the most stable conformation of the diastereomer?

I guess my main question is looking only at the newman projection how does one determine the stereochemistry? In the molecule to the right, I get for the first carbon, (et, H, Me,) R ( I flipped it ...
-1
votes
1answer
53 views

For group 13 elements M³⁺, why is the formation of MCl₄⁻ more favorable than for group 12 elements M²⁺?

I'm not a chemist and I'm trying to understand a chemistry point from a talk I went to recently. Any help would be much appreciated. The speaker was talking about $+3$ (Group 13) elements in the ...
0
votes
0answers
58 views

Effect of intramolecular hydrogen bonding on the stability of a molecule

What will be the effects of intramolecular hydrogen bonding on the stability of a molecule? Will it increase or decrease the overall stability of a molecule? Or will it not have any impact on the ...
0
votes
1answer
54 views

Is cis- or trans-cycloundecene more stable? [duplicate]

While reading about cis/trans isomerism in cycloalkenes, I came across the following statement: When the number of carbon atoms in a cycloalkane is less than 11, the cis form is more stable than ...
4
votes
1answer
177 views

How to determine the relative contribution of resonance structures when different rules give contradictory outcomes?

In order to determine the relative contributions of resonance structures, my textbook gives the following rules (in order): The more covalent bonds a structure has, the higher it scores. Structures ...
0
votes
0answers
30 views

Why are stable ionic charges so strongly related to the group number?

Why do lighter elements have ionic charges so strongly related to the group number? For example, why does $\ce{Al}$ only show +3 ionic charge? The basic concept of stability in an ionic compound is ...
1
vote
1answer
39 views

Thermal Decomposition of Sulfur Hexafluoride

What is the thermal decomposition temperature for $\ce{SF6}?$ I've heard it decomposes into $\ce{F2}$ and $\ce{SF4}$ only to decompose further into $\ce{S2}$ and $\ce{F2},$ but I haven't found much on ...
0
votes
1answer
164 views

Why does 2+ oxidation state become more stable relative to 3+ oxidation state for first row of transition metals? [duplicate]

I viewed an image showing all the possible oxidation states of each element in the first row of transition metals, and the main oxidation states highlighted in a different colour. I noticed all ...
1
vote
3answers
781 views

Acetone-resistant clear plastic

Is there a plastic that's clear, acetone resistant, and ideally sold in sheet stock that's ~1/8" or 1/4" thick? Both acrylic and polycarbonate are out, they turn cloudy on contact with acetone. I ...
0
votes
1answer
317 views

Why is iron pentacarbonyl known, but iron(III) hexacarbonyl is not?

Why is the neutral complex $\ce{[Fe(CO)5]}$ known, but the cationic carbonyl complex $\ce{[Fe(CO)6]^3+}$ is not known?
0
votes
0answers
31 views

Why doesn't anomeric effect predominate over steric effects in glucopyranose?

$\beta$-D-(+)-glucopyranose is more stable than $\alpha$-D-(+)-glucopyranose. Why is this? I know that in $\beta$-D-glucopyranose all the hydroxyl groups are in the equatorial position and thus it ...
-1
votes
2answers
506 views

What is the relation between solubility and thermal stability? [closed]

The thermal stability of alkaline earth metals increases down the group for hydroxides i-e., Be(OH)2 is less stable than Ba(OH)2. The solubility also increases down the group for these compounds i-e., ...
12
votes
1answer
642 views

What are the properties of COₓ where x ≥ 3?

$\ce{CO_x}$ are part of the oxocarbon molecule class. Commonly known are $\ce{CO}$ and $\ce{CO2}.$ However, there are molecules in which $x$ is equal to or larger than $3.$ Those molecules are barely ...
0
votes
2answers
292 views

Why hyperconjugation can't stabilize carbanion?

If Resonance can stabilize both carbo cation and anion then why can't hyperconjugation stabilize carbanion ? Since both Resonance and Hyperconjugation are pretty much the same, i.e both involve ...
1
vote
0answers
53 views

Stable physiological buffer to make NAD+ solution

I was wondering what would be the most stable physiological buffer for nicotinamide adenine dinucleotide (NAD+), for potential storage as frozen aliquots - 6 months stability or around there would be ...
1
vote
0answers
69 views

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 ...
7
votes
1answer
121 views

Are all stable Xenes (graphene-like 2D honeycomb sheets) buckled?

background: Per this abstract Silicene, germanene and stanene are part of a monoelemental class of two-dimensional (2D) crystals termed 2D-Xenes (X = Si, Ge, Sn and so on) which, together with ...
5
votes
0answers
60 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 ...
1
vote
0answers
76 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 of the ligand ...
1
vote
1answer
135 views

What is the stability order of the carbocation and carboanion?

So I came up with examples as below: 1 2 Now I am confused about the +I and -I effect in these structures since to my knowledge it can only be applied when there is a substituent (I might be wrong)...
1
vote
0answers
48 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 ...
0
votes
0answers
67 views

Stability of alkenes

The following question was asked on myPAT website: I started with the solution by counting the hyper-conjugative structures available to each alkene. Based on this concept only, order is: I > ...
0
votes
0answers
99 views

What is the order of stability of the cyclobutyl and cyclopropyl carbocations?

I know about the exceptional stability of Cyclopropylmethyl carbocation. In some books it is given that cyclopropyl and cyclobutyl carbocations are highly unstable due to their high strain. That ...

1
2 3 4 5
8