What defines a polar covalent bond?

A polar covalent bond is defined by the characteristics that arise when two nonmetals with different electronegativities share electron pairs. In this type of bond, the electrons are not shared equally; instead, the atom with the higher electronegativity attracts the shared electrons more strongly. This unequal sharing results in a partial negative charge on the more electronegative atom and a partial positive charge on the less electronegative atom, giving rise to the "polar" nature of the bond.

This definition is crucial in understanding the behavior of molecules, as the presence of polar covalent bonds can greatly influence a molecule's physical properties, such as its solubility and boiling point. Recognizing that a polar covalent bond is formed specifically between nonmetals with differing electronegativities helps clarify the distinction from bonds that involve more equal sharing of electrons or complete transfer.