Polar or nonpolar, is SO2?

Hello friends, In the field of chemistry, you may have various doubts regarding the polarity of particular compounds. Many of us are uncertain about the polarity of SO2 (sulfur dioxide). In order to clear up any confusion regarding the polarity of SO2, I will offer my knowledge.

Is SO2 polar or nonpolar? Due to the difference in electronegativity between sulphur and oxygen atoms, SO2 has a polar character. The larger the difference in electronegativity, the higher the molecule’s polarity. SO2 has a curved form as a result of the repulsion between the sulphur and oxygen atoms’ unpaired electrons. The form of a molecule also determines whether or not it is polar.

Why is SO2 a polar molecule?

In the SO2 molecule, both Sulfur and Oxygen have six electrons in their respective empty shells. 4 sulphur electrons form covalent bonds with the two pairs of oxygen electrons surrounding sulphur.

And after bonding in the SO2 molecule, Sulfur and Oxygen retain their uneven charges. There are two unpaired electrons remaining on the Sulfur atom and four on each of the Oxygen atoms.

Consequently, uneven charge distribution occurs following the SO2 molecule’s bonding. The lone pair on the Sulfur atom and the lone pair on the Oxygen atom repel each other.

Oxygen is more electronegative than Sulfur; hence, the Oxygen-Sulfur bond has an uneven charge distribution and is polar.

The VSEPR hypothesis states that the repulsion between two lone pairs is larger than that between a lone pair and a bond pair.

In a similar manner, the lone pair present on the Sulfur and Oxygen atoms in SO2 causes repulsion between them.

When more than one lone pair group is present, as in the case of SO2, the molecule has a somewhat different geometrical structure than when all groups are bonded.

Influencing factors of the polarity of a chemical compound

Polarity of a molecule is determined by the unequal distribution of charges among its constituent atoms. The unequal distribution of charges results in a net dipole moment.

The molecule whose net dipole moment is greater than zero is polar, whereas the molecule whose net dipole moment equals zero is non-polar. CO2 and O2 are examples of molecules that are non-polar.

Due to the non-polarity of CO2, the article may be read aloud.

The molecules with a zero net dipole moment have an equal distribution of charges on their atoms. Therefore, the dipole moment is cancelled out, resulting in a dipole moment that is net zero.

Dipole moment = Bond length * each element’s charge

The dipole moment of SO2 (sulphur dioxide) is calculated to be 1.6 debyes.

Understanding that the difference in electronegativity is one of the primary factors that impact polarity is preferable.

The polarity of a molecule is proportional to the difference in electronegativity between its constituent atoms.

Polarity and non-polarity of a molecule are determined by different factors, such as size and shape.

The geometry of the molecule’s molecular structure.

The number of atoms that are identical.

The quantity of lone pairs in the molecule.

The structure of the molecule’s symmetry.

In chemistry, electronegativity is a measurement of an atom’s ability to attract an electron to itself.

More electronegative atoms can attract electrons strongly, while less electronegative atoms can attract electrons only weakly.

SO2 Bond Angle

Trigonal planar is the shape of the SO2 molecule. The lone pair repulsion between Oxygen and Sulfur generates a curved shape with an angle of around 119 to 120 degrees.

The location of the atoms in SO2 is such that the Sulfur atom is between the two Oxygen atoms.

Nevertheless, the lone pair on the Sulfur atom repels the lone pair on the Oxygen atoms, resulting in the V-shaped/bent-shaped SO2 molecule.

SO2 has a bond angle of 120 degrees.

You should also refer to the article on the lewis structure of SO2 for further information on the geometry, hybridization, and lewis structure of SO2.

Polar and Nonpolar Substances

Everyone should be aware that when two atoms create a bond, they essentially share electrons.

Additionally, it is essential to remember that two different atoms do not share the electron of each other equally. It is due to the difference in electronegativity.

Compared to the atom with lower electronegativity, the atom with greater electronegativity attracts the pair of bound electrons toward itself.

According to previous research, the bond formed between two atoms is polar covalent if the difference in electronegativity is between 0.5 and 1.6.

The centre of negative charge in this bond is not at the centre. It would be at the end of an atom whose electronegativity is stronger.

And if the difference in electronegativity is smaller than 0.5, the bond is nonpolar covalent. If the difference in electronegativity is more than 2, the bond is ionic.

In the case of SO2, for instance, Oxygen has a stronger electronegativity than Sulfur, which makes it polar. Sulfur has an electronegativity of 2.58 while oxygen has an electronegativity of 3.44.

And in the case of NaCl, because the Chlorine atom has a stronger electronegativity than the Sodium atom, it attracts the shared electron pair towards itself.

As you advance to the right on the periodic table of chemistry, the electronegativity of elements increases, which is an important fact for science students to keep in mind.

In addition, as one progresses up the periodic table, the electronegativity of the elements increases.

Therefore, if you wish to determine if a molecule is polar or not, you must examine its polarity.

You should record the electronegativity of the atoms in the molecule, as well as the number of lone pairs and bonds.

And the molecule’s overall geometrical shape. This information is adequate for determining whether the molecule is polar or non-polar.


In this post, I’ve attempted to address the polarity of sulphur dioxide, the factors that influence its polarity, how to determine the polarity of a molecule, and the information necessary to draw a conclusion.

I hope I have clarified all of your questions regarding the polarity of SO2 and made you aware of the fundamentals of polar and nonpolar bonding.

Read more: Structure, Molecular Geometry, and Hybridization of N2 Lewis

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.


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