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, ...

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Stabilisation of phenoxide ion

Which one of the following substituents at para-position is least effective in stabilizing the phenoxide ion $\ce{PhO-}$ (a)$\ce{-CH3}$ (b)$\ce{-OCH3}$ (c)$\ce{-COCH3}$ ...
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54 views

Bond Strength of Carbon bonding

Please sort these bonds in decreasing order of their bond strengths... 1.$\ce{C#O}$ 2.$\ce{C#N}$ 3.$\ce{N#N}$ 4.$\ce{C-C}$ 5.$\ce{C-H}$ My attempt to the question - $\ce{C#O} ...
2
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1answer
68 views

Why is RS- more basic than RO-?

The basic strength is determined by the ability of an ion or molecule to accept a proton. How do I know whether RSH is more stable than ROH? (R is an alkyl group)
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1answer
25 views

What is more stable: a carbonate ion or a sulphate ion?

The sulphate ion has more number of resonance structures than the carbonate ion. Hence, it should be more stable than the carbonate ion. But my book says that the carbonate ion is stronger than the ...
3
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1answer
53 views

Hyper conjugation in acetic acid?

While comparing the relative stabilities of acetic acid and formic acid why don't we consider the 3 possible hyper conjugative structures which would stabilize the positive charge on carbon thus ...
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8 views

Why Bari centre is considered as Zero energy level?

Why the degenerate energy level of d orbitals before forming complex is considered zero? what advantages are there for taking the mean of t2g and eg orbitals as zero?
4
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1answer
58 views

Why is 2-methylpropene less in energy than its alkene counterparts?

Other isomers include 1-butene, cis 2-butene, and trans 2-butene. Why would 2-methylpropene be less in energy if there is more steric hindrance?
4
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1answer
75 views

Is there an experiment that visibly shows the effects of metastability?

I am attempting to create an experiment to show the effects of metastability to a public audience and get people excited about science. More specifically, I am wondering if there is any sort of liquid ...
2
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1answer
70 views

Carbocation stability order

I was wondering whether the following order is correct : In the first inequality, how come 9 hyperconjugation dominated resonance effect of benzene ring? In the last inequality doesn't 2 ...
4
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2answers
90 views

Which is more stable ? - A carbanion on benzene ring or a carbanion on a vinylic carbon on an aliphatic chain?

I came across a question which asks to work out the stability order for the following species. Can the lone pair on benzene carbanion participate in resonance? - If yes how and how is it more stable ...
2
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1answer
40 views

Does resonance overrule hyper conjugation in terms of stability in alkenes?

Which of the following is more stable ? $\ce{CH2=C(CH3)-CH=CH2}$ $\ce{CH3-CH=CH-CH3}$ I was going for answer 2 because it has 6 hyper conjugative effects. I found the answer given to ...
2
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1answer
37 views

Trihalide of Nitrogen

Which is the least stable trihlide of nitrogen and why ? I have two conflicting theories , one is that Fluorine-fluorine electron repulsion will make NF3 least stable and another is steric reasons of ...
2
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2answers
72 views

Does the compound KFO₃ exist?

As the compound potassium chlorate exists, is there something as $\ce{KFO3}$? All the other halogenates are mentioned somewhere on the web but what about this? If no, then why?
4
votes
2answers
200 views

Why does SnCl2 occur despite the octet rule?

Shouldn't reaching an octet be any atom's "goal"? However, I've recently learned about cases that are either expanding octets, or have lesser than "enough" electrons for an octet abiding. e.g.: S in ...
6
votes
1answer
70 views

Stability of di-substituted alkenes

Well I know for a fact that cis alkenes are less stable than trans alkenes due to steric repulsions. But what bugs me is the fact that why systems such as 2-Methylprop-1-ene (where I believe steric ...
7
votes
1answer
387 views

Why are triamino compounds so rare?

I was doing a reaxys substructure search for the compound shown on the left below, with the 3 amines on 1 carbon. However, the closest I found were all trinitro compounds like on the right. I would ...
2
votes
1answer
96 views

How to determine number of alpha hydrogens in a cyclic compound?

How do we determine the number of alpha hydrogens in a compound? Where should we start the naming from? For example, In both these structures, I need to determine their stabilities based on their ...
0
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1answer
43 views

Resonance in Propenal

I do not understand why the 3rd canonical form of propenal has the oxygen atom donating an electon. Oxygen in electronagetive so instead of taking electrons why is it giving? Maybe this why it is ...
7
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3answers
186 views

How does Resonance stabilize a molecule?

How does resonance lower the potential energy of the molecule? Take $\ce{O3}$ as an example.
4
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1answer
65 views

C-H Bond Dissociation Energy varies with substitution

What is the reason behind it? "Among sp3 hybridized systems, methane has the strongest C-H bond. C-H bonds on primary carbons are stronger than those on secondary carbons, which are stronger than ...
1
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2answers
64 views

A paradox in the philosophy of instability

The heavier the atom, the more unstable it gets, right? That is not true about Uranium and we know it. I wondered why. A brief explanation stated that since more neutrons are there in the nucleus ...
1
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1answer
28 views

How to study Sodium hypochlorite stability with materials

first of all I'm not not sure to be in the right stack exchange site, but I'm a material engineering student and this year I have a project: choose a material for a container filled with Sodium ...
2
votes
1answer
47 views

What is lowest energy state, how does an atom gain it and what does it have to do with hybridization?

I understand that hybridisation occurs due to the atom wanting to exist in the most stable state possible, and the most stable state has the lowest energy. What I don't understand, however, is say, in ...
6
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1answer
878 views

What kind of chemicals would exist at the heat death of the universe?

As the universe reaches the maximum entropy, presumably only the most stable chemicals would exist. Assume that all the elements haven't turn into iron yet, what kind of chemicals would dominate at ...
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0answers
48 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 ...
9
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2answers
648 views

By what mechanisms can molecules with the same empirical formula be so different?

I understand the difference between empirical and chemical formula. But I always thought that compounds and molecules took their specific shape because it's the lowest energy configuration. How then, ...
5
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3answers
968 views

Is a single atom stable?

It is well known that single atom of oxygen is not stable, and it forms $\ce{O2}$ molecule. But elements like carbon form a network of repeated bonds. As answered in another question, last atoms in ...
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4answers
643 views

Why are DCM and Chloroform so resistant against nucleophilic substitutions?

In the book Organic Chemistry by J. Clayden, N. Greeves, S. Warren, and P. Wothers I found the following reasoning: You may have wondered why it is that, while methyl chloride (chloromethane) ...
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0answers
56 views

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 ...
3
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2answers
135 views

How can two electrons lie together in an orbital?

Two electron of opposite spin can lie in a single orbital.. But what about the electron-electron repulsion. Okay! I got that the nuclear charge rather the large Z-effective overcome this repulsion by ...
1
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3answers
614 views

How does chlorine form more than 1 bond?

How are perchlorate or chlorate or chlorite ions and their respective acids or compounds formed. $\ce{Cl}$ can't form more than one bond but still... $\rightarrow$'Perchlorate ion' ...
2
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1answer
79 views

Conformational analysis determining forces

So the determining forces in the conformational analysis (what will be the more stable state and what will be the more excited state) according to my textbook are: Steric interaction Electron ...
4
votes
2answers
606 views

Why is O2 a biradical?

$\ce{O2}$ has a double bond in its normal form. That is $\ce{O=O}$. There are no unpaired electrons in this case are there since there are 2 lone pairs on each oxygen. However 1 resonance structure ...
1
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1answer
48 views

Why do all medicines require storage temperatures below 25 °C?

Almost all medicines I buy have storage requirements saying $T\le25^\circ C$. But do they really spoil at higher temperatures? What if they are stored at e.g. $30^\circ C$, which is common at ...
5
votes
1answer
134 views

What stable arrangements of hydrogen-bonded water exist in the range of 4-20 water molecules?

Water clusters made up of various numbers of water molecules have been described. Are all of these structures theoretical? What experimental evidence supports any of these structures? How does the ...
9
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1answer
318 views

Is BCl₅ possible?

Is $\ce{BCl5}$ possible? I saw it in book. As far as we can see there is no way to get 5 chlorine atoms with boron.
0
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1answer
35 views

Is there a possible effect of low frequency mechanical vibration on the stability of organic molecules

Is there a possible theoretical effect of mechanical vibration on the stability of organic molecules. E.g. some medicines degrade if they are not stored in a fridge, is there a theoretical ...
3
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1answer
173 views

Why is N₂ stable but HCN and C₂H₂ unstable?

Compounds with triple bonds generally seem to be unstable. $\ce{HCN}$ and $\ce{C2H2}$ are high-energy, relatively short-lived molecules that will readily polymerise or react with other organic ...
1
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1answer
50 views

Why is Technetium unstable?

Technetium is probably the most awkward element of the periodic table for me. It seems to me that Technetium is an exception, in the sense that it doesn't have any stable isotopes, despite having a ...
2
votes
2answers
140 views

Acidity of aldehydes

Which is more acidic between methanal ($\ce{HCHO}$) and ethanal ($\ce{CH3CHO}$). Please explain using General organic chemistry basic concepts. My Effort: I saw the stability of the conjugate base. ...
1
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2answers
84 views

How can a phase be thermodynamically stable at room temperature if it only appears at high temperature?

How can a phase that appears at high temperature be thermodynamically stable at room temperature? For example, $\alpha$-alumina is a phase that is formed at temperatures above $1000^\circ C$. How is ...
1
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2answers
125 views

Stability of transition metals in aqueous solution

Which is more stable in aqueous solution $\ce{Cr^{3+}}$ or $\ce{Mn^{3+}}$? And why? My approach: $\ce{Cr^{3+}}$ should be more stable as the 3d electrons will enter the $t_{2g}$ orbitals. Due to CFSE ...
5
votes
3answers
521 views

Stability of cyclobutyl methyl carbocation

I know that cyclopropyl methyl carbocation is exceptionally stable compared to say, benzyl carbocation. But I want to know how stable is cyclobutyl methyl carbocation compared to say, ...
3
votes
1answer
248 views

Thermodynamic stability of benzene ring

In learned that when benzene undergoes hydrogenation, $208KJ$ of energy is given off and thus $152KJ$ less energy than what would be given off if Kekule's structure was correct. My confusion is that ...
2
votes
2answers
212 views

delocalised electrons and benzene's stability

In most high school chemistry books, it is said that the delocalised electrons in benzene makes it particularly stable. However, how does it contribute to stability? Is there any simple way of ...
4
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1answer
225 views

Variable oxidation state of transition metal ions

Transition metals can form stable ions with different oxidation states. But I am confused why doesn't only the most stable state exist. Let me clarify my question more: $$\ce{Ti^{2+} -> Ti^{3+} + ...
1
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1answer
173 views

Why Fe(CO)5 exists, but Fe(NH3)5 doesn't?

Like in title: Why $\ce{Fe(CO)5}$ exists, but $\ce{Fe(NH3)5}$ doesn't? Edit: As Jan Dvorak pointed out, it may exist. If so: why is it so unstable?
2
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1answer
399 views

Stability of Allenes and Alkynes,

In Allenes, the $\ce{C=C=C}$ structure makes sure that the $p$-orbital of central carbon overlaps with 2 other carbons and the $p$-orbital of central carbon spreads out over the 3 carbons. In ...
5
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3answers
289 views

Why are noble gases stable

I was recently asked the question "Why are noble gases stable? with the expectation of providing an answer beyond the general explanation of "they have full valence layers" and I couldn't think of ...
7
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1answer
1k views

Resonance stability: ester vs. thioester

My problem set solution cites: "Although sulfur is less electronegative than oxygen, overlap is a more important consideration. Sulfur is a member of the third period. As a consequence, a ...