Knowing the i3 Lewis structure and understanding its physical properties, hybridization, and molecule shape is critical. We are getting to undergo the Lewis structure of I3 today, or we also realize it as a Tri-iodide ion because it’s a charge thereon. There are three iodine molecules during this molecule, which is why Tri-iodide is that the name of the compound.

What is the Lewis Structure?

The structure of Lewis may be a reflection of molecular electrons. There are lone pairs and valence electrons that assist in determining the molecule’s hybridization and form. Since there are iodine molecules, there’ll be one iodine molecule within the center. Iodine is additionally within the periodic table’s seventh group and has seven valence electrons in its outer orbit.

We have three iodine molecules here, alongside an additional electron that provides a charge. therefore the total number of electrons of valence is: 7 * 3 + 1 = 22.

The total number of valence electrons is 22 during this molecule. Now there’s an octet law that’s followed by an atom. Per atom should have eight electrons in its outer orbit, as per this law?

If within the outer shell of the central atom there are 8 electrons, there are two other atoms that require to finish their octet. As all atoms need eight electrons in their outer shell to finish the octet, both the neighboring iodine atoms will take one electron from the central iodine atom. that might say 8-1-1=6.


Since the electrons are taken from both atoms.

So now there’ll be six of the valence electrons on the central iodine atom. The lone pairs of electrons which don’t bind will form these six electrons. there’ll be three lone pairs and two bond pairs of electrons as each iodine atom features a bond with the central atom sharing one electron each with a complete of 3 lone pairs and a couple of bond pairs on the central atom because it forms the pair of electrons now.

Hybridization of I3 Lewis Structure

There are many formulas for understanding the Hybridization of any molecular.  This formula is used to figure out the number of hybridizations that help to understand the molecule’s hybridization.

The numbers of the hybrid and the hybridization it defines are as follows:

  1. Hybridization in sp
  2. Hybridization sp2
  3. Hybridization sp3
  4. Hybridization

The number finding formula is,

Number of hybridization: valence electron number + monovalent + (negative charge)-(positive charge)/2

The iodine atoms’ valence electrons are 7 since there are seven electrons within the outermost shell. Since two out of three iodines are monovalent, the monovalent atom number is 2.

It has a negative charge now once we get to the charge of the I3-ion, therefore the amount of this charge would be 1.

Now, consistent with the formula, position all the values

7 + 1 + 2 /2 2/2

=10/2/2 =


Therefore, the hybridization number is 5, which suggests that sp3d is hybridization.

Using lone pairs and valence electrons, differently to seek out the hybridization of a given molecule is. during this molecule, the amount of lone pairs is 3, and therefore the number of valence electrons sharing atoms is 2.

Thus, 3+2=5, which also specifies the hybridizations of sp3d?

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The shape of I3

The molecule shape I3- is linear in form. There are three atoms of iodine, of which one has a further charge. There are 3 lone pairs of electrons and a couple of bond pairs thanks to this one extra electron, which makes it steric number 5. These pairs attempt to repel one another the maximum amount possible since there are three lone pairs on the central Iodide atom.

So the pairs take equatorial positions to be away at a greater distance, and therefore the other two iodine atoms are 180 degrees from one another . the general sort of the I3-ion is thus linear.

I3 Lewis Structure
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The polarity of I3 Lewis Structure

So here’s the tricky thing about this ion, we should always call it a polyatomic ion rather than calling it a molecule, first of all, love it as a charge on it. the fees on the molecules that we see are ions. Since I3- has one electron, this ion has an overall charge. Molecules have polarity because all of them have charges that are partly charged positively and partly charged negatively.

Depending upon the separation of the fees on the atom, there’s a dipole moment on the molecules. The moment would even be larger if the space between both charges is bigger.

But the I3-ion may be a negatively charged ion once we mention it. We don’t see any moment of the polar bonds in it because the total charge itself is negative on the ion, even once we draw its Lewis structure. So it’s not polar or nonpolar either. Nevertheless, if you’ve got to define the ion, you’ll use the term sort of a polar molecule because I3- is water-soluble.

Properties of Tri-Iodide Ion

Let us discuss those characteristics of the triiodide molecule.

  1. The triiodide ion, from which most polyiodides exist, is that the simplest polyiodide. It appears yellow within the low concentration and brown within the solutions within the higher concentration. The blue-black color is liable for the triiodide ion, a well-known one that happens when iodine solution interacts with starch, or when iodine solutions within the non-polar solution don’t occur.
  2. Lugol’s iodine contains a stoichiometric quantity of elemental iodine and iodide, so this solution contains a large amount of triiodide ion.
  3. Iodine tincture, which may be a nominal solution of elemental iodine in ethanol, also contains an outsized amount of tri iodide thanks to its iodide and water content.

Lone Pairs of I3

There are three lone pairs of electrons in an iodine atom. The central atom in I3(-) has 3 lone electron pairs and produces two bonds with adjacent iodine. It, therefore, carries a negative charge thereon. Thus, the entire number of lone electron pairs within the I3 structure is 9.

I3 is usually mentioned as ion triiodide. it’s a polyhalogen ion and is formed from three atoms of iodine. it’s formed by mixing iodide salts and iodine in a solution. it’s a linear atom and it’s formed by I2 and I(-) ion binding. In solution, triiodide is red. I(-) may be a donor atom during this molecule and I2 is an acceptor atom.

In the empty d orbital of iodine, the electrons are accommodated. The central atom gains a charge whose value is 1. during the mixture of iodine atoms. Tri iodide ion hybridization is SP3D. With a bond angle of 180 degrees, the geometry of tri-iodide ions is linear.

Frequently Asked Question (FAQs)

Below you get some most common questions about the I3 Lewis Structure which can also helps the students of chemistry.

Does i3 have an octet in its entirety?

Lewis Dot of Triiodide Ion I3- The octet rule isn’t followed by me. more than 8 electrons will hold it. At the 4th energy state, iodine with valence electrons also will have access to the 4d sublevel, thus allowing quite 8 electrons.

Is i3 nonlinear or linear?

For 5 regions of electron density, I3- has 2 bonds and three lone pairs. The lone pairs go equatorial and the other two I atoms go axial, placing this into a trigonal bipyramidal structure. The molecule is linear, with three atoms during a line


In closing remarks, I3 Lewis Structure- may be a polyatomic ion that has 22 valence electrons, 3 lone pairs, 2 bond pairs, and sp3d hybridization, to sum up, this complete article. In shape, it’s linear and has no polarity.

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