Science, Tech, Math › Science Polar Molecule Definition and Examples Share Flipboard Email Print Emilija Randjelovic / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 21, 2020 A polar molecule is a molecule containing polar bonds where the sum of all the bond's dipole moments is not zero. Polar bonds form when there is a difference between the electronegativity values of the atoms participating in a bond. Polar molecules also form when the spatial arrangement of chemical bonds leads to a more positive charge on one side of the molecule than the other. Examples of Polar Molecules Water (H2O) is a polar molecule. The bonds between hydrogen and oxygen are distributed so that the hydrogen atoms are both on one side of the oxygen atom rather than evenly spaced. The oxygen side of the molecule has a slight negative charge, while the side with the hydrogen atoms has a slight positive charge.Ethanol is polar because the oxygen atoms attract electrons because of their higher electronegativity than other atoms in the molecule. Thus the -OH group in ethanol has a slight negative charge.Ammonia (NH3) is polar.Sulfur dioxide (SO2) is polar.Hydrogen sulfide (H2S) is polar. Carbon dioxide is made up of polar bonds, but the dipole moments cancel each other out. Therefore it is not a polar molecule. Predicting Polarity and Nonpolarity Whether a molecule is polar or nonpolar is a matter of its geometry. If one end of the molecule has a positive charge while the other end has a negative charge, the molecule is polar. If a charge is evenly distributed around a central atom, the molecule is nonpolar.