Is I2 a polar or nonpolar substance?

Iodine is a naturally occurring element found in seawater, as well in some rocks and sediments. We may often see references to it in various table salt commercials. However, a query about its polarity used to frequently cross my thoughts.

I obtained my answers after doing some investigation. And I’m going to share those answers with you in this piece. So let’s get started by providing detailed answers to your questions.

Is iodine nonpolar or polar? Iodine (I2) is a nonpolar molecule because it is a diatomic molecule with a linear, symmetric form. Because both iodine atoms have the same proportion of charge and electronegativity, the net dipole moment of the I2 molecule is zero, resulting in a nonpolar molecule.

Iodine is the heaviest of the stable halogens, having an atomic mass of 126.90 and an atomic number of 53. Iodine is currently produced mostly in Chile and Japan.

It is also employed as a non-toxic radiocontrast material due to its high atomic number and ease of attaching to organic molecules. It is required for the manufacture of thyroid hormones, in addition to its industrial usage.

Iodine shortage can cause intellectual impairments.

Iodate minerals, brackish water from oil and salt wells, and natural brine deposits left by the evaporation of ancient oceans are the main sources of iodine.

It’s made commercially by extracting iodine vapour from processed brine or releasing iodine from iodate derived from nitrate ores.

Let’s go on to a more extensive explanation of iodine’s non-polar nature.

Molecules, Polar and Nonpolar

Polar Molecule: A polar molecule is generated when one of the molecule’s ends has a higher number of positive charges than the other (negative charges).

As a result, they come up with the idea for an electrical pole. The origin of the negative charge in such a molecule with a polar link could be on either side. On the other hand, the positive charge’s centre would be on the opposite side.

NonPolar Molecule: A molecule with no charges at the end because the electrons are closely scattered and symmetrically balance each other out.

A polar molecule cannot be mixed with a non-polar molecule in a solution.

Consider the difference between water and oil. The polar molecule in this solution is water. Oil, on the other hand, behaves like a non-polar molecule.

There isn’t a solution between these two molecules. It’s to prevent them from becoming confused. You can also read about the polarity of water in this article.

And because oil is nonpolar, it does not interact with water. Examine the reason for Oil’s non-polarity.

What causes I2 to be nonpolar?

The fundamental reason for iodine’s non-polar nature is that it only requires one more electron in its outer orbital ([Kr] 4d10 5s2 5p5) to complete the octet, therefore two iodine molecules will share two electrons equally to obtain stability.

Furthermore, because both have the same electronegativity, there will be no net partial charge, making I2 nonpolar.

Electronegativity refers to an atom’s ability to attract electrons to its side.

As a result, both Iodine atoms are identical in all characteristics, have equal effect on the electron bound pair, and share equally, leaving no partial charge on any atom.

Still having trouble grasping the concept? Don’t worry, I’ll go over it again so you have a clear image of what’s going on!

What determines whether a molecule is polar or nonpolar?

Let’s look at the components that determine whether a molecule is polar or nonpolar.

To begin, a molecule’s polarity, shape, and dipole moment determine whether it is polar or nonpolar. A molecule is nonpolar if it meets the following criteria:

Cancelling the polar links will result in a nonpolar molecule if the arrangement is symmetrical.

When diatomic molecules are produced, both atoms have the same charge intensity.

Atoms with the same electronegativity will have a net-zero dipole moment.

An asymmetrical molecule with an electronegativity difference between the bound atoms, on the other hand, will result in a polar molecule.

With the example of oxygen, we can gain a sense of “sharing equal electrons.” Because oxygen has 6 electrons in its outer shell, it requires 2 more to complete the octet.

To achieve stability, two oxygen atoms share a total of four electrons. The image below will demonstrate the same!

Iodine now has seven electrons in its outer orbital, which is 5s2 5p5. In order to produce a stable iodine molecule, both iodine atoms must share two electrons. As a result, they form a covalent connection.

Take a look at the graphics below for a visual representation of the above-mentioned hypothesis!

When it comes to electronegativity, because they are both the same atom in a molecule, they will have the same electronegativity of 2.5.

As a result, EN= 2.5 – 2.5 = 0, there will be no net partial charge, making iodine non-polar.

To learn more, polar molecules have atoms with various electronegativities, show charge separation, and so have a dipole moment.

Is there a dipole moment in I2?

Both iodine atoms are linked at a 180° angle, as can be seen in the attached photograph.

With a linear configuration, there will be a net-zero dipole moment because each of them have the same electronegativity value.

When there is a charge separation and a difference in electronegativity, a dipole moment occurs. The dipole moment grows in proportion to the electronegativity.

The dipole moment of a molecule is largely determined by its geometrical structure. Symmetric molecules, despite their polar links, can never have a net dipole.

Iodine has a symmetric structure, which means there is no net dipole.

Iodine’s Chemical Properties (I2)

Bernard Courtois, a well-known scientist, discovered iodine in 1811.

It frequently reacts with a variety of elements in order to complete the octet, and it is a powerful oxidising agent.

However, as compared to stable halogens, it is the least effective oxidizer.

An iodine molecule can reversibly separate a pair of iodine atoms at high temperatures.

In CCl4, I2 dissolves to produce a vivid violet solution.

In these liquids, the absorption band maxima occurs in the 520-540 nm region.

When I2 reacts with Lewis bases, the I2 peak shifts blue, and a new peak (230-330 nm) emerges.

The production of adducts, also known as charge-transfer complexes, causes this.

Instead of water, iodine can be dissolved in organic solvents.

Iodine also doesn’t conduct electricity since it doesn’t have any mobile delocalized electrons.

Is there a London dispersion force for iodine (I2)?

The weak London dispersion force is the only intermolecular attraction that maintains two iodine atoms together.

There is no probability of a dipole-dipole interaction because it is a non-polar molecule.

When it comes to the London dispersion force, it’s a form of Van der Waals force that’s quite weak.

The I2 molecule has enough electrons to generate this force and hold the molecule together. However, because this force isn’t very strong, this molecule has a low melting and boiling point.

Is it true that I2 dissolves in water?

When it comes to iodine’s solubility in water, we can claim that it is almost insoluble.

To dissolve iodine, water’s hydrogen bonds must be disrupted in order to obtain iodine between H2O molecules.

However, breaking the link will need too much energy, which will not be compensated by the development of a new bond between water and iodine.

Because no hydrogen bonds are broken, iodine can be dissolved in organic solvents.

Only the dispersion forces between iodine and hexane must be broken, and they must be replaced by equivalent forces between the two.

Iodine also doesn’t conduct electricity since it doesn’t have any mobile delocalized electrons.

Iodine’s Applications (I2)

Iodine salts are employed in medications and disinfectants, and iodine is widely used in industry.

It’s employed as a catalyst in a variety of processes.

It’s also utilised as an animal feeding supplement.

It’s utilised in printing inks and dyes, as well as photographic chemicals.

Polarizing filters for LCD panels are also made from it.


All of the foregoing data point to the conclusion that I2 is non-polar in nature. The property of equal sharing of electrons between two iodine atoms to obtain stability is the reason behind this. There is also no net dipole moment, making I2 non-polar, due to the identical electronegativity and linear structure.

If you have any questions about the polarity of iodine, please contact us. Please feel free to ask them any questions you may have, and I will gladly respond!

Read more: Molecular Geometry, Hybridization, and Polarity of KCl Lewis Structure

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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