Polar Bond
Definition and meaning of Polar Bond in chemistry.
A polar bond is a type of covalent chemical bond where a pair of electrons is unequally shared between two atoms due to a difference in their electronegativities.
In more detail
The atom with the higher electronegativity pulls the shared bonding electrons closer to its own nucleus, developing a partial negative charge. Consequently, the less electronegative atom develops a partial positive charge of equal magnitude, thereby creating a permanent bond dipole. If a molecule contains multiple polar bonds that do not cancel out completely through symmetrical geometry, the entire molecule will exhibit a net dipole moment and be considered a polar molecule.
Key facts
| Field | General Chemistry |
|---|---|
| Cause | Electronegativity difference |
| Formula Example | HCl |
In a molecule of hydrogen chloride (HCl), the chlorine atom is significantly more electronegative than the hydrogen atom, resulting in a polar bond where chlorine carries a partial negative charge.
Frequently asked questions
What electronegativity difference indicates a polar covalent bond?
Typically, an electronegativity difference between 0.4 and 1.7 indicates a polar covalent bond.
Can a molecule with polar bonds be nonpolar overall?
Yes, if the polar bonds are arranged symmetrically, their dipole moments can cancel out, as seen in carbon dioxide.