How To Draw A Hydrogen Bond On Chemdraw

Learning Objective

Describe the properties of hydrogen bonding.

Key Points

Hydrogen bonds are strong intermolecular forces created when a hydrogen atom bonded to an electronegative atom approaches a nearby electronegative atom.
Greater electronegativity of the hydrogen bond acceptor volition pb to an increase in hydrogen-bail force.
The hydrogen bail is one of the strongest intermolecular attractions, but weaker than a covalent or an ionic bond.
Hydrogen bonds are responsible for holding together DNA, proteins, and other macromolecules.

Terms

hydrogen bondThe allure between a partially positively charged hydrogen cantlet attached to a highly electronegative atom (such equally nitrogen, oxygen, or fluorine) and another nearby electronegative cantlet.
electronegativityThe tendency of an atom or molecule to draw electrons towards itself, class dipoles, and thus form bonds.
intermolecularA type of interaction between two unlike molecules.

Forming a Hydrogen Bond

A hydrogen bond is the electromagnetic attraction created betwixt a partially positively charged hydrogen atom attached to a highly electronegative atom and another nearby electronegative atom. A hydrogen bond is a type of dipole-dipole interaction; it is not a true chemical bond. These attractions tin can occur between molecules (intermolecularly) or within dissimilar parts of a unmarried molecule (intramolecularly).

**Hydrogen bonding in water**This is a infinite-filling ball diagram of the interactions between separate h2o molecules.

Hydrogen Bond Donor

A hydrogen atom attached to a relatively electronegative atom is a hydrogen bail donor. This electronegative cantlet is usually fluorine, oxygen, or nitrogen. The electronegative atom attracts the electron cloud from around the hydrogen nucleus and, by decentralizing the deject, leaves the hydrogen atom with a positive partial accuse. Because of the small size of hydrogen relative to other atoms and molecules, the resulting charge, though only partial, is stronger. In the molecule ethanol, there is one hydrogen cantlet bonded to an oxygen atom, which is very electronegative. This hydrogen atom is a hydrogen bail donor.

Hydrogen Bond Acceptor

A hydrogen bail results when this strong partial positive charge attracts a lone pair of electrons on another atom, which becomes the hydrogen bond acceptor. An electronegative atom such as fluorine, oxygen, or nitrogen is a hydrogen bail acceptor, regardless of whether information technology is bonded to a hydrogen atom or not. Greater electronegativity of the hydrogen bond acceptor volition create a stronger hydrogen bail. The diethyl ether molecule contains an oxygen atom that is not bonded to a hydrogen atom, making it a hydrogen bond acceptor.

A hydrogen attached to carbon tin also participate in hydrogen bonding when the carbon cantlet is jump to electronegative atoms, as is the instance in chloroform (CHCl_iii). Every bit in a molecule where a hydrogen is attached to nitrogen, oxygen, or fluorine, the electronegative atom attracts the electron cloud from around the hydrogen nucleus and, by decentralizing the cloud, leaves the hydrogen cantlet with a positive partial accuse.

Interactive: Hydrogen BondingExplore hydrogen bonds forming between polar molecules, such as water. Hydrogen bonds are shown with dotted lines. Show partial charges and run the model. Where practise hydrogen bonds form? Try changing the temperature of the model. How does the pattern of hydrogen bonding explain the lattice that makes up ice crystals?

Applications for Hydrogen Bonds

Hydrogen bonds occur in inorganic molecules, such every bit water, and organic molecules, such as DNA and proteins. The two complementary strands of DNA are held together by hydrogen bonds betwixt complementary nucleotides (A&T, C&G). Hydrogen bonding in water contributes to its unique backdrop, including its high boiling betoken (100 °C) and surface tension.

**Water droplets on a foliage**The hydrogen bonds formed between water molecules in h2o aerosol are stronger than the other intermolecular forces between the water molecules and the foliage, contributing to high surface tension and distinct water droplets.

In biology, intramolecular hydrogen bonding is partly responsible for the secondary, tertiary, and quaternary structures of proteins and nucleic acids. The hydrogen bonds assistance the proteins and nucleic acids class and maintain specific shapes.