The key property of a water molecule that allows hydrogen bonds to form among adjacent molecules is its polarity. Water molecules have an uneven distribution of electrical charge due to the high electronegativity of the oxygen atom compared to the hydrogen atoms. This causes the oxygen atom to carry a partial negative charge, while the hydrogen atoms carry partial positive charges. Because of this polarity, the positively charged hydrogen atom of one water molecule is attracted to the negatively charged oxygen atom of a neighboring water molecule, forming a hydrogen bond
. Specifically:
- The oxygen atom attracts shared electrons more strongly, creating a partial negative charge (δ−).
- The hydrogen atoms have partial positive charges (δ+).
- This dipole nature leads to an electrostatic attraction between molecules.
- Hydrogen bonds form when the positive hydrogen of one molecule interacts with the negative oxygen of another
This hydrogen bonding is responsible for many of water's unique properties, such as cohesion, surface tension, and its high boiling point
. The bent shape of the water molecule and the presence of two hydrogen atoms allow each molecule to form hydrogen bonds with multiple neighbors, creating a dynamic network of interactions
. In summary, the polarity of the water molecule-specifically the partial positive charge on hydrogen atoms and partial negative charge on the oxygen atom-enables hydrogen bonds to form between adjacent water molecules.
