Which type of molecules can exhibit hydrogen bonding?

Hydrogen bonding is a specific type of dipole-dipole interaction that occurs when hydrogen is covalently bonded to highly electronegative elements such as nitrogen, oxygen, or fluorine. These electronegative atoms pull the electron density away from the hydrogen atom, resulting in a significant partial positive charge on the hydrogen. This positive charge allows the hydrogen atom to attract the lone pairs of electrons on nearby electronegative atoms, leading to hydrogen bonding.

Molecules containing N-H, O-H, or F-H bonds are capable of forming hydrogen bonds due to the presence of these highly electronegative atoms. The strong electronegativity of nitrogen, oxygen, and fluorine, combined with the small size of hydrogen, facilitates close contact and interaction between the molecules, making hydrogen bonds particularly strong compared to other types of intermolecular forces.

While C-H bonds are present in a variety of organic molecules, they do not lead to hydrogen bonding because carbon is not sufficiently electronegative to create a significant charge difference. Metallic bonds and polar molecules can involve other forms of intermolecular attraction, but they do not specifically result in hydrogen bonding like the bonds containing N-H, O-H, or F-H do.