Lewis structure of C2Cl2

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Lewis structure of C2Cl2
Lewis structure of C2Cl2

The Lewis structure of C2Cl2 contains one triple bond and two single bonds, with two carbons in the center, and each carbon is attached with one chlorine. There are three lone pairs on each chlorine atom, and the carbon atom does not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of C2Cl2.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Complete octet on central atom
#5 Calculate formal charge and check stability

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

  • Let’s calculate the total number of valence electrons

We know that… carbon is a group 14 element and chlorine is a group 17 element. Hence, carbon has four valence electrons and chlorine has seven valence electrons.

Now C2Cl2 has two carbon atoms and two chlorine atoms.

So the total number of valence electrons = (valence electrons of carbon atom × 2) + (valence electrons of chlorine atom × 2)

Therefore, the total number of valence electrons = 8 + 14 = 22

  • Now decide the central atom

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for carbon and chlorine as follows:

Electronegativity value of carbon = 2.55
Electronegativity value of chlorine = 3.16

Obviously, carbon is less electronegative than chlorine. Hence, assume that right carbon is the central atom (as there are two carbons).

So now, put two carbons in the center and two chlorines on either side. And draw the rough skeleton structure for the Lewis structure of C2Cl2 something like this:

Skeleton structure for Lewis structure of C2Cl2

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since two carbons are surrounded by two chlorines, use six electrons to show three chemical bonds as follows:

Three chemical bonds shown between atoms

#3 Mark lone pairs

As calculated earlier, we have a total of 22 valence electrons. And in the above structure, we have already used six valence electrons. Hence, sixteen valence electrons are remaining.

Two valence electrons represent one lone pair. So sixteen valence electrons = eight lone pairs.

Note that carbon is a period 2 element, so it can not keep more than 8 electrons in its last shell. And chlorine is period 3 element, so it can keep more than 8 electrons in its last shell.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are chlorines and left carbon, so each chlorine will get three lone pairs, and left carbon will get two lone pairs. And the central atom (right carbon) will not get any lone pair, because all eight lone pairs are used.

So the Lewis structure of C2Cl2 looks something like this:

Lone pairs marked on Lewis structure of C2Cl2

In the above structure, you can see that the octet is completed on outside atoms. But, the central atom (right carbon) doesn’t form an octet.

So in the next step, we have to complete the octet on the central atom.

#4 Complete octet on central atom

Remember that carbon is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Now right carbon already has four valence electrons. Hence, right carbon needs four more valence electrons to complete its octet.

So convert two lone pairs from the left carbon atom to make a new bond with the right carbon atom. And then, the Lewis structure of C2Cl2 looks something like this:

Lone pair of left carbon is converted, and octet is completed on atoms

In the above structure, you can see that the octet is completed on the central atom (right carbon), and also on the outside atoms. Therefore, the octet rule is satisfied.

After completing the octet, one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

#5 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

  • For each carbon atom

Valence electrons = 4
Nonbonding electrons = 0
Bonding electrons = 8

Formal charge = 4 – 0 – ½ (8) = 0

  • For each chlorine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of C2Cl2 looks something like this:

Formal charges are calculated, and got the stable Lewis structure of C2Cl2

In the above structure, you can see that the formal charges of both (carbon and chlorine) are zero. Therefore, this is the stable Lewis structure of C2Cl2.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

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Deep

Rootmemory.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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