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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.
One scheme gives the following somewhat arbitrary classification: those that are 15 to 40 kcal/mol, 5 to 15 kcal/mol, and >0 to 5 kcal/mol are considered strong, moderate, and weak, respectively. [18] Hydrogen bonds involving C-H bonds are both very rare and weak. [22]
A hydrogen bond (H-bond), is a specific type of interaction that involves dipole–dipole attraction between a partially positive hydrogen atom and a highly electronegative, partially negative oxygen, nitrogen, sulfur, or fluorine atom (not covalently bound to said hydrogen atom). It is not a covalent bond, but instead is classified as a strong ...
A solid with extensive hydrogen bonding will be considered a molecular solid, yet strong hydrogen bonds can have a significant degree of covalent character. As noted above, covalent and ionic bonds form a continuum between shared and transferred electrons; covalent and weak bonds form a continuum between shared and unshared electrons.
The hydrogen bond is often described as a strong electrostatic interaction. However, it also has some features of covalent bonding: it is directional, stronger than a van der Waals force interaction, produces interatomic distances shorter than the sum of their van der Waals radii , and usually involves a limited number of interaction partners ...
The bond length, or the minimum separating distance between two atoms participating in bond formation, is determined by their repulsive and attractive forces along the internuclear direction. [3] As the two atoms get closer and closer, the positively charged nuclei repel, creating a force that attempts to push the atoms apart.
An often studied dihydrogen complex of iron, [HFe(H 2)(dppe) 2] +.. The usual method for characterization is 1 H NMR spectroscopy.The magnitude of spin–spin coupling, J HD, is a useful indicator of the strength of the bond between the hydrogen and deuterium in HD complexes.
Bonding energies are significant, with solution-phase values falling within the same order of magnitude as hydrogen bonds and salt bridges. Similar to these other non-covalent bonds, cation–π interactions play an important role in nature, particularly in protein structure, molecular recognition and enzyme catalysis. The effect has also been ...