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  2. Hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_bond

    An ubiquitous example of a hydrogen bond is found between water molecules. In a discrete water molecule, there are two hydrogen atoms and one oxygen atom. The simplest case is a pair of water molecules with one hydrogen bond between them, which is called the water dimer and is often used as a model system. When more molecules are present, as is ...

  3. Low-barrier hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Low-barrier_hydrogen_bond

    At shorter distances, the barrier between the two energy minima is low enough that the hydrogen is equally bound as a low-barrier, or single-well hydrogen bond. A Low-barrier hydrogen bond (LBHB) is a special type of hydrogen bond. LBHBs can occur when the pKa of the two heteroatoms are closely matched, which allows the hydrogen to be more ...

  4. Symmetric hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Symmetric_hydrogen_bond

    A symmetric hydrogen bond is a special type of hydrogen bond in which the proton is spaced exactly halfway between two identical atoms. The strength of the bond to each of those atoms is equal. It is an example of a 3-center 4-electron bond. This type of bond is much stronger than "normal" hydrogen bonds, in fact, its strength is comparable to ...

  5. Alpha helix - Wikipedia

    en.wikipedia.org/wiki/Alpha_helix

    Since the α-helix is defined by its hydrogen bonds and backbone conformation, the most detailed experimental evidence for α-helical structure comes from atomic-resolution X-ray crystallography such as the example shown at right. It is clear that all the backbone carbonyl oxygens point downward (toward the C-terminus) but splay out slightly ...

  6. Molecular solid - Wikipedia

    en.wikipedia.org/wiki/Molecular_solid

    For intermolecular hydrogen bonds the δ+ hydrogen interacts with a δ- on an adjacent molecule. Examples of molecular solids that hydrogen bond are water, amino acids , and acetic acid. [ 3 ] [ 5 ] [ 8 ] [ 10 ] For acetic acid, the hydrogen (δ+) on the alcohol moiety of the carboxylic acid hydrogen bonds with other the carbonyl moiety (δ ...

  7. Chemical bond - Wikipedia

    en.wikipedia.org/wiki/Chemical_bond

    Hydrogen bonds of the form A--H•••B occur when A and B are two highly electronegative atoms (usually N, O or F) such that A forms a highly polar covalent bond with H so that H has a partial positive charge, and B has a lone pair of electrons which is attracted to this partial positive charge and forms a hydrogen bond. [23]: 702 Hydrogen ...

  8. Hydrogen compounds - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_compounds

    Hydrogen compounds are compounds containing the element hydrogen. In these compounds, hydrogen can form in the +1 and -1 oxidation states. Hydrogen can form compounds both ionically and in covalent substances. It is a part of many organic compounds such as hydrocarbons as well as water and other organic substances.

  9. Intermolecular force - Wikipedia

    en.wikipedia.org/wiki/Intermolecular_force

    A hydrogen bond is an extreme form of dipole-dipole bonding, referring to the attraction between a hydrogen atom that is bonded to an element with high electronegativity, usually nitrogen, oxygen, or fluorine. [4] The hydrogen bond is often described as a strong electrostatic dipole–dipole interaction.