hydrogen bondZoomA-Z

Subject - General Chemistry, Biochemistry

Interactions of the type D-H···|A between a proton donor D–H and a proton acceptor |A are called hydrogen bonds. D and A are generally strongly electronegative atoms like F, O, and N. In many hydrogen bonds, the distance between atoms A and D is shorter than the Van der Waals radii of A and D (distance criterion). In addition to structural studies (giving the A–D distance and the A–H–D angle), the existence of hydrogen bonds can also be detected spectroscopically.

Typical energies of hydrogen bonds D-H···A are between 10 and 50 $kJmol-1$. The strongest of all hydrogen bonds is the F-H···F bridge in the hydrogen fluoride ion (161 $kJmol-1$). The bonding energy of a hydrogen bond is comprised of electrostatic contribution (dipole-dipole and dipole-ion interactions) and covalent contribution (three-centre four-electron bond).