What is Hydrogen bond: Definition and 20 Discussions

A hydrogen bond (or H-bond) is a primarily electrostatic force of attraction between a hydrogen (H) atom which is covalently bound to a more electronegative atom or group, and another electronegative atom bearing a lone pair of electrons—the hydrogen bond acceptor (Ac). Such an interacting system is generally denoted Dn–H···Ac, where the solid line denotes a polar covalent bond, and the dotted or dashed line indicates the hydrogen bond. The most frequent donor and acceptor atoms are the second-row elements nitrogen (N), oxygen (O), and fluorine (F)
Hydrogen bonds can be intermolecular (occurring between separate molecules) or intramolecular (occurring among parts of the same molecule). Depending on the nature of the donor and acceptor atoms which constitute the bond, their geometry, and environment, the energy of a hydrogen bond can vary between 1 and 40 kcal/mol. This makes them somewhat stronger than a van der Waals interaction, and weaker than fully covalent or ionic bonds. This type of bond can occur in inorganic molecules such as water and in organic molecules like DNA and proteins. Hydrogen bonds are responsible for holding such materials as paper and felted wool together, and for causing separate sheets of paper to stick together after becoming wet and subsequently drying.
The hydrogen bond is responsible for many of the anomalous physical and chemical properties of compounds of N, O, and F. In particular, intermolecular hydrogen bonding is responsible for the high boiling point of water (100 °C) compared to the other group 16 hydrides that have much weaker hydrogen bonds. Intramolecular hydrogen bonding is partly responsible for the secondary and tertiary structures of proteins and nucleic acids. It also plays an important role in the structure of polymers, both synthetic and natural.

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  1. user366312

    How can I calculate hydrogen bonds in a specific direction w.r.t. a C-

    I need to calculate H-bonds in a specific direction of a C-alpha atom of a protein. And, I need to calculate that from a PDB file. Can anyone give me a general guideline/direction/idea regarding how to do that? N.B. I need to write a python program.
  2. P

    Hydrogen bonding in human skin

    if the human skin consists of hydrogen, then why does not happen hydrogen bond through contact with something or with another person?
  3. D

    What is Hydrogen Bond Auto-correlation function?

    Can somebody explain the Hydrogen bond Auto-correlation function in Computational Chemistry (Molecular Dynamics and Simulations) and what does Intermittent and Continuous Hydrogen bond means? Why the graph decays over time? and it's applications?
  4. S

    Van der Waals vs. Hydrogen bonds

    I know that the two are different thing, that vdW appears in inert gas crystals and alike while hydrogen bond bonds molecules of water. My question is, how does the potential look for hydrogen bond? For vdWaals we have the two terms proportional to 1/R^6 that describes attraction and 1/R^12...
  5. D

    Why does the potential energy get lower as atoms get closer?

    Hello. I'm new to this forum and to Physics and Chemistry in general and I have a question that's making me go crazy: why does the potential energy decrease as two atoms (say, hydrogen atoms) get closer to form a molecule? I'm talking about this graphic: I've read that it's related to the...
  6. S

    I Bond length of a hydrogen bond

    Hello, in ice I have read that the average bond length of the hydrogen bond is about 2 Angstroms. This is roughly twice the O-H (covalent) bond length. My question is what really determines the length of the hydrogen bond? Why wouldn't the hydrogen be drawn closer to the next water...
  7. HelloCthulhu

    Diamagnetism and Hydrogen Bond Strength

    I've read a few papers regarding the effects of a uniform magnetic field on water solutions, but I'm a complete illiterate when it comes to deciphering the jargon. So far, many papers confirm that a uniform magnetic field strengthens hydrogen bonds and can increase the redox potential. I've...
  8. S

    Why is the fluorine atom a poor hydrogen bond acceptor?

    My notes states that fluorine is too highly electronegative and hence clings on too tightly to its lone pair of electrons and so it cannot accept hydrogen bonds as well. However, it also stated that a hydrogen bond will be stronger if the electron density on the electron rich atom the stronger...
  9. P

    Does acidity and hydrogen bond strength go hand in hand?

    More acidity means more electronegativity, and more electronegativity means more dipole moments. I observed that liquids with low dipole moments (bases) often have lower density and surface tension, but not necessarily hydrogen bonds. To contradict it, acetic acid have a low surface tension but...
  10. P

    Hydrogen Bond Strength: Strengthen & Weaken in Water

    How do you strengthen and weaken hydrogen bonds in water aside from changing its temperature? Could you add any solutes to do so?
  11. D

    Acyl chloride and hydrogen bond

    Homework Statement why acyl chloride can't form hydrogen bond? there's C=O , which O atom can form hydrogen bond . am i right?Homework Equations The Attempt at a Solution
  12. gauss44

    Can sulfur participate in a hydrogen bond?

    I googled it and got both answers, "yes" and "no." What I mean is: O-H-S, F-H-S, N-H-S, etc. Ex.'s of "yes": http://www.ncbi.nlm.nih.gov/pubmed/19089987 [PLAIN]http://pubs.rsc.org/en/content/artic.../ce/c0ce00760a[/URL] Ex. of "no": http://www.nature.com/nature/journal.../149218a0.html
  13. D

    Hydrogen bond between tetrafluoromethane and water

    Homework Statement My textbook wrote that haloalkanes are generally insoluble in water.It is because the polar C-X bonds are not polar enough to make the haloalkanes soluble in water. Consider tetrafluoromethane Difference in electronegativity between F and C = 4.0 - 2.5 = 1.5 Difference in...
  14. J

    Hydrogen bond vs dipole-dipole?

    I saw a video on youtube saying water molecules were held together by hydrogen bonding, not dipole dipole. Why is that?
  15. K

    Hydrogen bond big problems in my mind

    I have two big problems in my mind about hydrogen bond for many years. I have checked many textbooks but all of them fails to explain what I don't understand. 1. To form a hydrogen bond (particular strong attraction) Why it is necessary for a hydrogen atom to attach to a highly...
  16. L

    Why HCl is not a hydrogen bond

    Cl gets similar electronegativity as N, NH3 is a hydrogen bond, but HCl isn't, why? N and Cl also gets lone pair electrons! N and Cl is more or less the same. Could anybody please answer this question? Okay, if I rephrase it, it will become why the bonding between H and Cl isn't hydrogen...
  17. J

    Can sodium sulphate, p-toluidine, and benzoic acid form hydrogen bond

    can sodium sulphate, p-toluidine, and benzoic acid form hydrogen bond with water?
  18. B

    How can something hydrophobic hydrogen bond?

    1) The nitrogenous bases of DNA hydrogen bond with each other yet they are also characterized as hydrophobic? How can something hydrophobic hydrogen bond? 2) How many chromosomes are present in a human somatic cell after S phase (DNA replication). Is it still 46 or 92?
  19. M

    Why Does Water Expand When it Freezes?

    I read that water expands when it freezes due to it's hydrogen bond. What on Earth (or ocean, for that matter) does a hydrogen bond have to do with becoming less dense with freezing :confused: ? Please explain taking into consideration that I haven't taken chem. since 10th grade. Thanks!
  20. denian

    Hydrogen Bonding in CH3-C=O-CH3 and Its Role in Intermolecular Interactions

    just a simple question. can CH3- C=O - CH3 molecules form hydrogen bond with H2O?