Lewis structure of COCl2

The information on this page is ✔ fact-checked.

The Lewis structure of COCl₂ contains one double bond and two single bonds, with carbon in the center, and oxygen and two chlorines on either side. There are three lone pairs on each chlorine atom, and two lone pairs on the oxygen atom.

Steps

By using the following steps, you can easily draw the Lewis structure of COCl₂:

#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, oxygen is a group 16 element, and chlorine is a group 17 element. Hence, carbon has four valence electrons, oxygen has six valence electrons, and chlorine has seven valence electrons.

Now COCl₂ has one carbon atom, one oxygen atom, and two chlorine atoms.

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

Therefore, the total number of valence electrons = 4 + 6 + 14 = 24

• 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, oxygen, and chlorine as follows:

Electronegativity value of carbon = 2.55
Electronegativity value of oxygen = 3.44
Electronegativity value of chlorine = 3.16

Obviously, carbon is less electronegative than oxygen and chlorine. Hence, assume that carbon is the central atom.

So now, put carbon in the center and oxygen and two chlorines on either side. And draw the rough skeleton structure for the Lewis structure of COCl₂ something like this:

Also read: How to draw Lewis structure of BH₃ (3 steps)

#2 Show chemical bond

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

#3 Mark lone pairs

As calculated earlier, we have a total of 24 valence electrons. And in the above structure, we have already used six valence electrons. Hence, eighteen valence electrons are remaining.

Two valence electrons represent one lone pair. So eighteen valence electrons = nine lone pairs.

Note that both (carbon and oxygen) are the period 2 elements, so they can not keep more than 8 electrons in their last shell. And chlorine is a 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 oxygen and two chlorines, so oxygen and two chlorines will get three lone pairs. And the central atom (carbon) will not get any lone pair, because all nine lone pairs are used.

So the Lewis structure of COCl₂ looks something like this:

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

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

Also read: How to draw Lewis structure of NCl₃ (4 steps)

#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 carbon already has six valence electrons. Hence, carbon needs two more valence electrons to complete its octet.

So convert one lone pair from the oxygen atom to make a new bond with the carbon atom. And then, the Lewis structure of COCl₂ looks something like this:

Here, the lone pair of oxygen is converted (instead of chlorine). This is because oxygen is less electronegative than chlorine, and so it can give more electrons to share them.

In the above structure, you can see that the octet is completed on the central atom (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.

Also read: How to draw Lewis structure of BrF₅ (4 steps)

#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 carbon atom

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

Formal charge = 4 – 0 – ½ (8) = 0

• For oxygen atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 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 COCl₂ looks something like this:

In the above structure, you can see that the formal charges of all atoms are zero. Therefore, this is the stable Lewis structure of COCl₂.

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

📝 Your feedback matters. Visit our contact page.

Related

• Lewis structure of BH₃
• Lewis structure of NCl₃
• Lewis structure of BrF₅
• Lewis structure of BrF₃
• Lewis structure of HF

External video

• COCl2 Lewis Structure – How to Draw the Lewis Structure for COCl2 – YouTube • Wayne Breslyn

External links

• The Lewis Structure of COCl2 [with free study guide and video] – AceOrganicChem
• COCl2 Lewis structure, molecular geometry, hybridization, bond angle – Topblogtenz
• What is the Lewis structure for COCl2? – Homework.Study.com
• COCl2 Lewis Structure in 6 Steps (With Images) – Pediabay
• COCl2 Lewis Structure, Molecular Geometry, Hybridization, and Polarity – Techiescientist
• Chemical Bonding: COCl2 Lewis Structure – The Geoexchange
• Draw the Lewis structure for COCl2, including lone pairs – Chegg
• Lewis Structure for COCl2 – Laurence Lavelle
• How to Calculate the Formal Charge of CoCl2 – Sciencing
• COCl2 Geometry and Hybridization – Chemistry Steps
• Draw the Lewis structure for COCl2, including lone pairs – Brainly
• CoCl2 Lewis Structure, Molecular Structure, Hybridization, Bond Angle and Shape – Geometry of Molecules
• What is the molecular shape of COCl2? – Quora
• Draw the Lewis structure for COCl2, including lone pairs – OneClass