hydrogenbindinger

Hydrogenbindinger, a term used in some languages for hydrogen bonds, are noncovalent interactions formed when a hydrogen atom attached to an electronegative atom (donor) interacts with a lone pair on a second electronegative atom (acceptor). They are weaker than covalent bonds but stronger than most van der Waals interactions.

Donors are typically O-H and N-H groups, with fluorine-containing hydrogens rarely forming strong bonds. Acceptors include lone pairs on electronegative atoms such as oxygen, nitrogen, and occasionally sulfur. The interaction is directional, becoming strongest when the donor-acceptor angle is close to 180 degrees.

Bond strengths vary widely, commonly about 4 to 40 kilojoules per mole, with water around 20 kJ/mol per bond. Distances between donor and acceptor atoms are typically 2.7 to 3.2 angstroms. Hydrogenbindinger can be intramolecular, reinforcing specific conformations, or intermolecular, linking molecules into networks.

In biology and chemistry, these bonds govern the properties of water, mediate DNA base pairing (A-T two bonds, G-C three bonds), and stabilize protein secondary structures and molecular recognition. They also influence ice structure, proton transport, and the assembly of many polymers and crystals.

Analytical methods such as infrared spectroscopy detect changes in O-H and N-H vibrational frequencies as hydrogenbindinger form or break. Nuclear magnetic resonance, calorimetry, and structural methods complement these data. Understanding hydrogenbindinger is central to chemistry, biochemistry, materials science, and drug design.