21
votes
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Why is the boiling point of stibane higher than that of ammonia?
Though it does go against your intuition, you've actually mentioned the answer in your question. Stibane has a higher boiling point than ammonia/azane on account of van der Waals interactions (owing ...
- 18k
19
votes
Accepted
Can an amide nitrogen be a hydrogen bond acceptor?
If I understood you correctly, you are talking about the peptide bond nitrogens ($\ce{R-C(=O)-\color{red}{N}H-R}$). This is, reduced to its significant chemical functional group an amide, more ...
- 64.3k
19
votes
Do symmetric hydrogen bonds in neutral molecules exist?
This question crossed my mind during a lab today because we were making $\ce{Ni(dmg)2}$, which is shown below.
Well first, this is charged in some sense, but it is net-neutral. Also, the ...
- 12.6k
18
votes
Do symmetric hydrogen bonds in neutral molecules exist?
It appears that perhaps water may have symmetric hydrogen bonds between oxygen atoms, but it would take at least 60 GPa of pressure, or more, to make water to bond like that. I guess water stops being ...
- 4,414
16
votes
Accepted
Is hydrogen bonding generally defined to include only three period two elements?
I don't think there is any such traditional definition requiring $\ce{N}$, $\ce{O}$ or $\ce{F}$.
For example, in table 7 and the discussion thereof in Hydrogen Bonding Annual Review of Physical ...
- 39k
15
votes
Accepted
Is a hydrogen bond considered to be a van der Waals force?
According to the IUPAC gold book a van der Waals force is:
The attractive or repulsive forces between molecular entities (or between groups within the same molecular entity) other than those due to ...
- 10.1k
15
votes
Why does hydrogen fluoride have a boiling point so much lower than that of water?
I think there are a variety of qualitative ways of looking at this:
Perhaps the most obvious is that $\ce{H2O}$ can form a greater number of hydrogen bonds due to having an equal numbers of hydrogen ...
- 17.8k
14
votes
Accepted
How can the hydrogen bonds in solid HF be best represented?
At Wikipedia you find this structure (drawn by Benjah-bmm27 on Wikimedia Commons):
In the crystal, there is a hexagonal lattice of these chains, so the packing of the fluorine (green spheres) has an ...
- 17.3k
14
votes
Accepted
Is Hydrogen Bonding a Type of Dipole Dipole Interaction?
Well, it turns out that this is a very active area of research. I will only summarize what I understand to be true about the covalent nature of the hydrogen bond, so I'm sure the explanation could be ...
- 12.6k
13
votes
Accepted
How to identify hydrogen bonds and other non-covalent interactions from structure considerations?
It is safe to say that there will always be intermolecular forces at play. At the time where you will consider these you should already have a good idea about the molecules involved in your system.
...
- 42.4k
12
votes
Accepted
Does hydrogen bonding strength correspond to Brønsted basicity in a given medium?
@Dissenter, you really need to stop asking questions like this. Once again you point out that the emperor has no clothes! :)
It turns out that the mechanism of simple proton transfer is an active ...
- 82.2k
12
votes
Accepted
Are there any other elements that get less dense in their solid state?
Your terminology is a little off: water isn't an element.
There isn't really a simple single explanation of why some solids are less dense than their associated liquids. The general explanation (which ...
- 32.6k
12
votes
Is there intramolecular hydrogen bonding in salicylaldehyde?
It can indeed hydrogen bond, this can (to a certain extent) be observed by NMR. Due to the internal hydrogen bonding, the phenolic proton is surprisingly consistent, and shows no dependence on ...
- 16.7k
12
votes
Accepted
Does ammonia exhibit hydrogen bonding in its gaseous state?
The paper[1] referenced by Nilay Ghosh says that,
it is well known that hydrogen bonds commonly exist in ammonia clusters and play an important role
and gives a picture of some of the clusters that ...
- 12.6k
11
votes
How does intramolecular hydrogen bonding cause the molecules to be separated from each other?
Molecules with inter-molecular hydrogen bonds tend to associate with one another, while molecules with intra-molecular hydrogen bonds tend to associate with themselves.
Ortho- and para-nitrophenol ...
- 82.2k
11
votes
Accepted
Why can't alcohols form hydrogen-bonded dimers like carboxylic acids?
The strength of a hydrogen bond somewhat depends on the $\ce{X-H\bond{...}X}$ angle that the hydrogen-bonding hydrogen forms with the two electronegative elements $\ce{X}$. In our case, carboxylic ...
- 64.3k
11
votes
Is a temperature decrease required for hydrogen bonds to form in water?
You are right, in a sense.
A more accurate statement would be that as the temperature decreases, the average lifetime of a hydrogen bond increases. Thus, on average the liquid/solid/molecule will be ...
- 12.6k
11
votes
Solubility of ortho- and para-nitrophenol in benzene
It turns out that the opposite of what happens in polar solvents takes place when a non-polar solvent is used. At the same temperature, o-nitrophenol is more soluble in benzene than it's m and p ...
- 5,971
10
votes
Strength of hydrogen bonding in phenol or methanol
Let me answer the second question first, because the answer is so much easier: Of course the hydrogen bond strength depends among others upon the carbon oxygen is attached to. Consider phenol and ...
- 64.3k
10
votes
Do symmetric hydrogen bonds in neutral molecules exist?
In Schaefer's paper,[1] which you linked, the authors describe nitromalonamide as being the compound with the lowest calculated barrier to intramolecular proton transfer, or tautomerisation.
Earlier ...
- 66.2k
10
votes
Accepted
Which dicarboxylic acid has the most acidic hydrogen?
The $\mathrm pK_\mathrm a$ of the $\ce{CH2}$ group in a dicarbonyl compound is roughly $10$, whereas the $\mathrm pK_\mathrm a$ of a carboxylic acid is roughly $5$. For example, dimethyl malonate has ...
- 66.2k
10
votes
Accepted
Why isn't Indigo soluble in water?
True, Indigo can form hydrogen bonds, but with what? Is it water? Nope.
It makes hydrogen bonds with itself.
This makes the molecule incapable of bonding with water. Not only that, but the molecule ...
10
votes
Accepted
Do amines or alcohols have stronger intermolecular hydrogen bonds?
The boiling point of non-ionic compounds are highly depend on their H-bonding abilities. For example, boiling point of water (molar mass: $\pu{18.02 g/mol}$) is $\pu{100 ^\circ C}$ at $\pu{1 atm}$ ...
- 35.3k
10
votes
Do amines or alcohols have stronger intermolecular hydrogen bonds?
Mathew Mahindaratne has provided analysis based on experimental values of the boiling points of the two compounds. I would like to offer a different view using bonding analysis.
Before I begin ...
- 9,444
9
votes
Accepted
Hydrogen bonding in staggered vs eclipsed conformations
Disclaimer: I am not a computational chemist, I am completely new to this stuff. Just a humble student of @pentavalentcarbon
However, my thought is that if you have interacting OH groups, the ...
- 8,307
9
votes
Accepted
Why hydrogen bonding in some acids make them a stronger acid when it is present even before deprotonation?
Some of the conformers of salicylic acid are given below, all of which are planar in configuration.$\mathrm{^{[1]}}$
Although the compound can adopt several conformations the first conformer(in the ...
- 437
8
votes
Accepted
SN1 Polar Protic Solvent Stabilization of Substrate
I know that the standard textbook answer is that a polar protic
solvent is able to better stabilize/solvate carbocations through
hydrogen bonding.
In an $\ce{S_{N}1}$ reaction, a polar protic ...
- 82.2k
8
votes
Accepted
Does hydrogen bonding only occur between water molecules?
NO, Water is not only the example for hydrogen bonding. It's most common example for basics.
Hydrogen bonds occur in DNA, proteins, polymers, etc. But for introductory level it is easy to explain ...
- 4,997
8
votes
Accepted
Why is a ketone not capable of hydrogen bonding among themselves?
Short answer: the ketone oxygen can participate in hydrogen bonding
The compound you mention, methoxymethane, is an ether not a ketone.
Ethers don't hydrogen bond very well because the oxygen isn'...
- 82.2k
8
votes
Accepted
Why do Asn-Ser and Gln-Thr have different H bonding patterns?
I don't have the textbook you've gotten this from, but unless there's a statement to the contrary, I suspect these are intended as examples of hydrogen bonding, rather than an exhaustive list of the ...
- 4,746
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