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4
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2answers
59 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
votes
1answer
23 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
votes
1answer
28 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 ...
4
votes
2answers
181 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 ...
5
votes
1answer
51 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
383 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
67 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
votes
1answer
40 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 ...
6
votes
3answers
157 views

How does Resonance stabilize a molecule?

How does resonance lower the potential energy of the molecule? Take $\ce{O3}$ as an example.
2
votes
1answer
51 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
vote
2answers
62 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
vote
1answer
27 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
votes
1answer
875 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 ...
2
votes
0answers
44 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
votes
2answers
644 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
votes
3answers
963 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 ...
11
votes
4answers
540 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) ...
1
vote
0answers
53 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
votes
2answers
130 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
vote
3answers
549 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
votes
1answer
74 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
565 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
vote
1answer
43 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
133 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 ...
8
votes
1answer
312 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
votes
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
votes
1answer
166 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
vote
1answer
49 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
139 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
vote
2answers
74 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
vote
2answers
112 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
495 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
226 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 ...
1
vote
2answers
192 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
votes
1answer
213 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
vote
1answer
168 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
votes
1answer
381 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
votes
3answers
251 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
votes
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 ...
2
votes
1answer
219 views

Which is most stable conformation of optically inactive Butane–2,3–diol?

The most stable conformation of optically inactive Butane–2,3–diol is: (A) (B) (C) (D) I choose C as the correct answer but, in the answer key it given to be B. C is the staggered form and the ...
8
votes
3answers
2k views

Is oxygen with a positive charge more stable? (comparison of canonical structures)

Which of the contributing structures of the resonance below is more stable? I'm watching a video lecture by a professor of my college where he puts this question to the class. The class ...
8
votes
1answer
165 views

Phenyl vs methyl cis/trans stability

Compound I is obviously the Z isomer. I thought it was obviously the less stable one too, given that there's a phenyl and t-butyl on the same side. The answer says that since the phenyl is planar, ...
3
votes
2answers
192 views

Lone pair electrons on secondary carbon vs primary carbon

I know that a molecule is more stable when a free radical is on a secondary carbon over a primary carbon, but how about when there is a lone pair of elections that can be placed on a secondary or ...
3
votes
3answers
80 views

Are sulfonyl-carboxylates stable in water?

This time I am interested in a specific type of acid anhydride, sulfonyl-carboxylates, i.e. compounds with the following molecular structure: where R1 and R2 are organic substituents or hydrogen ...
2
votes
3answers
154 views

Are dicarbonyl amides stable in water?

Dicarbonyl amides, that is carboxylic acid anhydrides with their single-bonded oxygen between their carbonyl groups replaced with an amide group, I'm curious as to whether they're stable in water or ...
3
votes
1answer
243 views

Is it possible to create an acid anhydride that's stable in water and if so what conditions must its structure satisfy?

I ask this question because if acid anhydrides are always unstable in water then my interest, as a student of pharmacology, would be greatly diminished. Acid anhydrides are, in my books, at least, the ...
2
votes
1answer
604 views

What does reaction exothermicity say about the stability of molecules

If a reaction is exothermic it means that the energy state of the products is lower than that of the reactants so this will be the state that 'nature' will naturally strive for. Often you see that ...
6
votes
3answers
3k views

Normal Spinel and Inverse Spinel

According to my notes, [OCTAHEDRAL SITE STABILIZATION ENERGY (OSSE)], sterical effects and electronic effects in stability create a confusion in this theory. However, we are able to solve this problem ...
8
votes
5answers
22k views

Difference between thermodynamic and kinetic stability

What is the difference between thermodynamic and kinetic stability? I'd like a basic explanation, but not too simple. For example, methane does not burn until lit -- why?