Why Do Hydrogen Bonds Form?
Hydrogen bond refers to the attractive intermolecular energy existing between two parts of molecules with opposite charges of polarity. It is the interaction between hydrogen and an electronegative atom which has a partial negative charge. In order to create a bond, the hydrogen having the positive charge, must be covalently bonded to another electronegative atom which has the negative charge.
These electronegative atoms that form a bond between hydrogen atoms are called hydrogen-bond donors. This atom can either be oxygen, nitrogen or fluorine. Whether bonded to a hydrogen atom or not, the electronegative atom of these elements is a hydrogen bond acceptor. Example of this is the ethanol, a bond between hydrogen and oxygen. Diethyl Ether is an example of a hydrogen bond acceptor without hydrogen atom bonded to it.
These bonds can either happen intermolecularly or intramolecularly. Intermolecularly refers to the bond occurring between two different molecules. Example of an intermolecular bond is between hydrogen and oxygen. A hydrogen bond is responsible for the high boiling point of water which is at about 100 Ãƒ’šÃ‚°C.
Intramolecular bond refers to an attraction within the different parts of a single molecule. This type of bonding is responsible for stabilizing the secondary, tertiary and quaternary structures of proteins and nucleic acids. It is also involved in the process of enzyme catalysis.
The strength of a hydrogen bond is usually stronger than natural dipole energy between molecules but not as hard as normal covalent bonds within a molecule. It is much stronger than a van der Waals interaction but weaker than ionic or covalent bonds.
A hydrogen bond occurs in both cases of organic and inorganic molecules such as water and DNA.
In conclusion, hydrogen bonds form through an electrostatic interaction between a part of a covalent molecule and an electronegative atom.