CI4 lewis structure contains carbon atom at middle position whereas four iodine atoms surround to it. A total of 12 lone pairs and 4 bonded pairs are present in the lewis structure of CI4.
The lewis structure of CI4 is similar to CCl4 and CF4, since, they all are in the same group in the periodic table and contain the same number of valence electrons.
Follow some steps for drawing the Lewis dot structure for CI4
1. Count total valence electron in CI4
First of all, determine the valence electron that is available for drawing the lewis structure of CI4 because the lewis diagram is all about the representation of valence electrons on atoms.
So, an easy way to find the valence electron of atoms in the CI4 molecule is, just to look at the periodic group of carbon and iodine atoms.
As the carbon atom belongs to the 14th group in the periodic table and iodine is situated in the 17th group, hence, the valence electron for the carbon is 4, and for the iodine atom, it is 7.
⇒ Total number of the valence electrons in iodine = 7
∴ Total number of valence electrons available for the CI4 Lewis structure = 4 + 7×4 = 32 valence electrons [∴CI4 molecule has one carbon and four iodine atoms]
2. Find the least electronegative atom and place it at center
As we know, electronegativity increase as we move from left to right in the periodic table. Hence, the iodine atom is more electronegative than a carbon atom. Therefore, it can never be placed in a central position because it is less prone to share electrons.
So, place the carbon in the middle position and spread the four iodine atoms around it.
3. Connect outer atoms to central atom with a single bond
In this step, join all outer atoms to the central atom with the help of a single bond.
In, CI4 molecule, iodine is the outer atom, and carbon is the central atom. Hence, joined them.
Now look at the above structure and count the number of valence electrons we used till now. A single bond means 2 valence electrons. In the above structure, four single bonds are used for connecting each iodine atom to a carbon central atom.
Hence, (4 × 2) = 8 valence electrons are used from a total of 32 valence electrons that are available for drawing the lewis structure of CI4.
∴ (32 – 8) = 24 valence electrons
So, we are left with 24 valence electrons more.
4. Place remaining electrons on the outer atom first and complete their octet
In this step, we have to put the remaining valence electron over each outer atom to complete their octet first. We know, in the CI4 molecule, iodine is the outer atom, hence, each iodine atom needs 8 electrons in its outer shell to complete the octet and attain stability.
So, just start putting out the remaining valence electron around each iodine atom until they complete their octet.
So, by looking at the above structure, we see each iodine atom gets 6 valence electrons represented as dots, and they also have 2 valence electrons in form of a single bond that is attached to them.
Hence, (6 valence electrons as dots + one single bond that contains 2 electrons) = 8 valence electrons are present around each iodine atom, hence, they all completed their octet.
Also, the central atom Carbon also completed its octet as it has four single bonds attached that means, it has 8 valence electrons in its valence shell.
Now check the formal charge for the above CI4 lewis structure.
5. Check the stability with the help of a formal charge concept
“The lesser the formal charge on atoms, the better is the stability of the lewis diagram.”
To calculate the formal charge on an atom. Use the formula given below-
Let’s start with the central atom which is carbon in the CI4 molecule.
For carbon atom:
⇒ Valence electrons of carbon = 4
⇒ Lone pair electrons on carbon = 0
⇒ Shared pair electrons around carbon(4 single bond) = 8
∴ (4 – 0 – 8/2) = 0 formal charge on the carbon central atom.
Each iodine atom in the CI4 lewis structure has the same number of lone pair and bonded pair electrons, hence, just count formal charge for just one iodine atom
For iodine atom
⇒ Valence electrons of iodine = 7
⇒ Lone pair electrons on iodine = 6
⇒ Shared pair electrons around iodine (1 single bond) = 2
∴ (7 – 6 – 2/2) = o formal charge on each iodine atom.
CI4 lewis structure
So, each atom gets the formal charge equal to zero, hence, the above lewis structure of CI4 is the most stable and reliable.
The molecular geometry of CI4 is tetrahedral because the central atom carbon is bonded with four iodine atoms and it contains no lone pair that means, it is an AX4 type molecule.
A represent central atom
X represent the number of bonded atom to central atom
According to VSEPR theory or chart, the AX4 type molecule forms tetrahedral molecular geometry or shape.
Hybridization of CI4
The hybridization of CI4 is Sp3 because the steric number of the carbon central atoms is four.
The calculation of steric number is done by adding a number of bonded atoms attached to the central atom and lone pair on the central atom.
In the case of the CI4 molecule, carbon is the central atom that is attached to the four bonded atoms(iodine) and it has no lone pairs.
Hence, (4 + 0) = 4 is the steric number of central atom carbon in the CI4 molecule that gives Sp3 hybridization.
Is CI4 polar or nonpolar?
So, Is CI4 polar or nonpolar? CI4 has a tetrahedral molecular shape that is highly symmetrical, so all the dipoles of the 4 polar C-I bonds cancel each other out, resulting in an overall nonpolar molecule. Although the bond C-I is polar in nature because of the difference of electronegativity between them but the overall CI4 molecular is nonpolar.
Vishal Goyal is the founder of Topblogtenz, a comprehensive resource for students seeking guidance and support in their chemistry studies. He holds a degree in B.Tech (Chemical Engineering) and has four years of experience as a chemistry tutor. The team at Topblogtenz includes experts like experienced researchers, professors, and educators, with the goal of making complex subjects like chemistry accessible and understandable for all. A passion for sharing knowledge and a love for chemistry and science drives the team behind the website. Let's connect through LinkedIn: https://www.linkedin.com/in/vishal-goyal-2926a122b/
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