How to draw CaI2 Lewis Structure?

Drawing CaI2 Lewis Structure is very easy. Here in this post, we described step by step method to construct CaI2 Lewis Structure.

Key Points To Consider When Drawing The CaI2 Lewis Structure

A three-step approach for drawing the CaI2 Lewis structure can be used. The first step is to sketch the Lewis structure of the CaI2 molecule, to add valence electron around the calcium atom; the second step is to valence electron to the two iodine atoms, and the final step is to combine the step1 and step2 to get the CaI2 Lewis Structure.

The CaI2 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the CaI2 molecule. The geometry of the CaI2 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose a CaI2 geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the Ca-I bond (dipole moment properties of the CaI2 molecule). The calcium-iodine bonds in calcium iodide (CaI2), for example, are polarised toward the more electronegative iodine, and because both bonds have the same size and opposite to each other, their sum is zero due to the CaI2 molecule’s bond dipole moment, and the CaI2 molecule is classified as a nonpolar molecule.

The molecule of calcium iodide (with linear geometry) is tilted at 180 degrees and has a difference in electronegativity values between iodine and calcium atoms, with calcium’s pull being less than iodine’s terminal in the CaI2 molecule. As a result, it has no dipole moment. The CaI2 molecule has no dipole moment due to an equal charge distribution of negative and positive charges.

How to draw CaI2 Lewis Structure?

CaI2 Lewis Structure:

The central atom is calcium, which is bordered on two terminals with iodine atoms. Calcium has two outermost valence electrons, indicating that it possesses two electrons in its outermost shell, whereas iodine only has seven valence electrons in its outermost shell. To complete the octet of the iodine atom, an iodine terminal atom requires one electron. If you’re interested in learning more about the iodine octet rule, please see our previous post.

Two iodine atoms establish covalent connections with the calcium atom as a result, leaving the calcium atom without any lone pairs. There are no lone pairs on the calcium central atom that resist the bond pairs of the two Ca-I. According to VSEPR theory, no electronic repulsion leads the CaI2 molecule to take on a linear molecular shape like NO2+ and CS2.

The CaI2 molecule’s Ca-I bonds are arranged in a symmetrical order around the linear geometry, giving rise to the linear CaI2 shape. The CaI2 molecule has a linear molecular geometry because there is no electrical repulsion between them.

Electronegative Difference Calculation CaI2 Molecule:

Calcium has an electronegativity of 1.00, while iodine has an electronegativity of 2.66 in the CaI2 molecule. The difference in electronegativity can be estimated using the method below.

The electronegative value difference between calcium and iodine

Electronegativity value of calcium = 1.00

Electronegativity value of iodine= 2.66

Difference of electronegativity value between calcium and iodine= 2.66 – 1.00 =1.66

Electronegativity difference between Ca-I bond calculation of CaI2 molecule

Due to the difference in electronegativity value of greater than 0.5, the Ca-I bond of the CaI2 molecule becomes polar. Because of this difference in electronegativity, the CaI2 molecule’s Ca-I bond becomes polar. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of CaI2 is discussed in our previous post.

As a result, the Ca-I bond’s dipole moment is high due to the polarization of the bonds, and all Ca-I bonds’ dipoles are faced opposite to each other in the linear geometry. The CaI2 molecule’s total dipole moment is predicted to be 0 D. It has a partial negative charge for iodine atoms and a partial positive charge for the central calcium atom.

The electron dot structure of the CaI2 molecule is also known as the CaI2 Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the CaI2 molecule’s bond formation. The outermost valence electrons of the CaI2 molecule must be understood while considering the Lewis structure of the molecule.

The calcium atom is the middle element in CaI2 molecular geometry, with two electrons in its outermost valence electron shell, whereas the iodine atom has seven electrons in its outermost valence electron shell.

The CaI2 molecule has a total of 16 valence electrons as a result of the foregoing reasoning. With the core central calcium atom, the two-terminal iodine atoms form covalent bonds, leaving the calcium atom with no lone pairs on it.

The linear geometry and structure of the CaI2 molecules are similar to that of the carbon disulfide (CS2) molecule because no lone pairs of central calcium atoms create interaction with Ca-I bond pairs. The bond angle of the I-Ca-I bond is approximately 180 degrees. The Ca-I bond length is 181 pm(picometer).

To sketch the CaI2 Lewis structure by following these instructions:

Step-1: CaI2 Lewis Structure

To calculate the valence electron of each atom in CaI2, look for its periodic group from the periodic table. The alkaline earth metal and halogen families, which are the second and 17th groups in the periodic table, are both made up of calcium and iodine atoms. In their outermost shells, calcium and iodine have two and seven valence electrons, respectively.

Because calcium and iodine are members of the periodic table’s alkaline earth metals and halogen family groups, their valence electrons are two and seven, respectively.

Calculate the total number of electrons in the CaI2 molecule’s outermost valence shell. The first step is to determine how many electrons are in the CaI2 Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the CaI2 Lewis diagram. The CaI2 molecule’s core carbon atom can be represented as follows:

Total outermost valence shell electron of calcium atom in CaI2= 2

Total outermost valence shell electron of iodine atom in CaI2= 7

The CaI2 molecule has one central calcium atom and two iodine atoms. Then the total outermost valence shell electrons can be calculated as follows

∴ Total outermost valence shell electrons available for CaI2 Lewis structure( dot structure) = 2 +2*7= 16 valence electrons  in CaI2    

calculation of total valence electron of CaI2 molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of CaI2. We’ll choose the least electronegative value atom in the CaI2 molecule to place in the center of the CaI2 Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

How to draw CaI2 Lewis Structure?

Step-2: CaI2 Lewis Structure

As a result, calcium is the third atom in the periodic table’s alkaline earth metal family group. Iodine is the fourth member of the halogen family. The electronegative value of a calcium atom is lower than that of an iodine atom. Furthermore, calcium has a two electrons limit since iodine is the most electronegative element in the CaI2 molecule.

In a CaI2 Lewis structure diagram, the calcium atom can be the center atom. As a result, central calcium in the CaI2 Lewis structure, with all two iodines arranged in the two-terminal of linear geometry.

How to draw CaI2 Lewis Structure?

Step-3: CaI2 Lewis Structure

Connect the exterior and core central atom of the CaI2 molecule with two single bonds (Ca-I). In this stage, use two single bonds to connect all two iodine atoms on the outside of the CaI2 molecule to the central calcium atom in the middle.

Count how many electrons from the outermost valence shell have been used in the CaI2 structure so far. Each Ca-I bond carries two electrons because each calcium atom is connected to two iodine atoms by two Ca-I bonds. Bond pairings are what they’re called.

So, out of the total of 16 valence electrons available for the CaI2 Lewis structure, we used 4 for the CaI2 molecule’s two single (Ca-I) bonds. The CaI2 molecule has no lone pair electrons in the center calcium. We don’t need to put the extra electron in the molecular geometry of CaI2.

Place the valence electrons in the Ca-I bond pairs starting with the core calcium and two iodine atoms in the CaI2 molecule. In the CaI2 Lewis structure diagram, we always begin by introducing valence electrons from the central calcium atom. As a result, wrap around the central calcium atom’s bond pair valence electrons first.

Calcium requires 4 electrons in its outermost valence shell to complete the molecular stability. Calcium already shares 4 electrons thanks to the two single bonds. Then place the valence electron in the iodine atom, it placed around seven electrons. Totally, 12 valence electrons were placed on the two iodine atoms of the CaI2 molecule.

We’ve positioned four electrons around the central calcium atom, which is represented by a dot, in the CaI2 molecular structure above. The calcium atom completes its molecular stability in the CaI2 molecule because it possesses 4 electrons in its outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the CaI2 Lewis structure. Four electrons are shown as dots in the CaI2 chemical structure, whereas two single bonds each contain two electrons. The outermost valence shell electrons of the CaI2 molecule are 4 + 12= 16 as a result of the calculation.

How to draw CaI2 Lewis Structure?

So far, we’ve used 16 of the CaI2 Lewis structure’s total eight outermost valence shell electrons.

Complete the middle calcium atom stability and, if necessary, apply a covalent bond. The core atom in the CaI2 Lewis structure is calcium, which is bonded to the iodine atoms by two single bonds (Ca-I). With the help of two single bonds, it already shares four electrons. As a result, iodine follows the octet rule and has eight electrons surrounding it on the two terminals of CaI2.

How to calculate the formal charge in CaI2 Lewis Structure?

The formal charge on the CaI2 molecule’s calcium central atom often corresponds to the actual charge on that calcium central atom. In the following computation, the formal charge will be calculated on the central calcium atom of the CaI2 Lewis dot structure.

To calculate the formal charge on the central calcium atom of the CaI2 molecule by using the following formula:

The formal charge on the calcium atom of CaI2 molecule= (V. E(Ca)– L.E(Ca – 1/2(B.E))

V.E (Ca) = Valence electron in calcium atom of CaI2 molecule

L.E(Ca) = Lone pairs of an electron in the calcium atom of the CaI2 molecule.

B.E = Bond pair electron in Be atom of CaI2 molecule

calculation of formal charge on calcium atom in CaI2 molecule

The calcium core atom (two single bonds connected to iodines) of the CaI2 molecule has two valence electrons, zero lone pair electrons, and four bonding electrons. Put these values for the calcium atom in the formula above.

Formal charge on calcium atom of CaI2 molecule = (2- 0-(4/2)) =0

In the Lewis structure of CaI2, the formal charge on the central calcium atom is zero.


In this post, we discussed the method to construct the CaI2 Lewis structure. Need to remember that, if you follow the above-said method, you can construct molecular dot structure very easily.

What is the CaI2 Lewis structure?

CaI2 Lewis structure is dot representation

What is the formal charge on the CaI2 Lewis structure?

Zero charges on the CaI2 molecular structure

The polarity of the molecules

Polarity of the molecules are listed as follows

Lewis Structure and Molecular Geometry

Lewis structure and molecular geometry of molecules are listed below

External Reference:

Information on CaI2

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