Hydrogen bond

A hydrogen bond is a special type of attractive interaction (perhaps a variation of a dipole-dipole bond) that exists between an electronegative atom and a hydrogen atom bonded to another electronegative atom. This type of bond always involves a hydrogen atom, thus the name. Hydrogen bonds can occur between molecules (intermolecularly), or within different parts of a single molecule (intramolecularly). The typical hydrogen bond is stronger than van der Waals forces, but weaker than covalent or ionic bonds.

Intermolecular hydrogen bonding is responsible for the high boiling point of water (100 °C), as opposed to other group 16 hydrides. Intramolecular hydrogen bonding is partly responsible for the secondary, tertiary, and quaternary structures of proteins and nucleic acids.