Hydrogen Bonding Information Sheet Template printable pdf download

Hydrogen Bonding

A hydrogen bond is a special type of dipole-dipole attraction which occurs when a hydrogen atom bonded to a strongly

electronegative atom exists in the vicinity of another electronegative atom with a lone pair of electrons. These bonds are

generally stronger than ordinary

dipole-dipole

and

dispersion

forces, but weaker than true

covalent

and

ionic

bonds.

Introduction

For a hydrogen bond to occur there must be both a hydrogen donor and an acceptor present. The donor in a hydrogen

bond is the atom to which the hydrogen atom participating in the hydrogen bond is covalently bonded, and is usually

a strongly electronegative atom such as N, O, or F. The hydrogen acceptor is the neighboring electronegative ion or

molecule, and must posses a lone electron pair in order to form a hydrogen bond.

Since the hydrogen donor is strongly electronegative, it pulls the covalently bonded electron pair closer to its nucleus,

and away from the hydrogen atom. The hydrogen atom is then left with a partial positive charge, creating a dipole-dipole

attraction between the hydrogen atom bonded to the donor, and the lone electron pair on the acceptor.

Types of hydrogen bonds

Hydrogen bonds can occur within one single molecule, between two like molecules, or between two unlike molecules.

• Intramolecular hydrogen bonds: Intramolecular hydrogen bonds are those which occur within one single molecule.

This occurs when two functional groups of a molecule can form hydrogen bonds with each other. In order for this

to happen, both a hydrogen donor an acceptor must be present within one molecule, and they must be within close

proximity of each other in the molecule. For example, intramolecular hydrogen bonding occurs in ethylene glycol

(\(C_2H_4(OH)_2\)) between its two hydroxyl groups due to the molecular geometry.

• Intermolecular hydrogen bonds: Intermolecular hydrogen bonds occur between separate molecules in a

substance. They can occur between any number of like or unlike molecules as long as hydrogen donors and

acceptors are present an in positions in which they can interact. For example, intermolecular hydrogen bonds can

occur between \(NH_3\) molecules alone, between \(H_2O\) molecules alone, or between \(NH_3\) and \(H_2O\)

molecules.

Hydrogen Bonding Information Sheet Template