Lewis structure of NOCl

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The Lewis structure of NOCl contains one double bond and one single bond, with nitrogen in the center, and oxygen and chlorine on either side. The oxygen atom has two lone pairs, the nitrogen atom has one lone pair, and the chlorine atom has three lone pairs.

Steps

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

#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… nitrogen is a group 15 element, oxygen is a group 16 element, and chlorine is a group 17 element. Hence, nitrogen has five valence electrons, oxygen has six valence electrons, and chlorine has seven valence electrons.

Now NOCl has one nitrogen atom, one oxygen atom, and one chlorine atom.

So the total number of valence electrons = valence electrons of nitrogen atom + valence electrons of oxygen atom + valence electrons of chlorine atom

Therefore, the total number of valence electrons = 5 + 6 + 7 = 18

• 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 nitrogen, oxygen, and chlorine as follows:

Electronegativity value of nitrogen = 3.04
Electronegativity value of oxygen = 3.44
Electronegativity value of chlorine = 3.16

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

So now, put nitrogen in the center and oxygen and chlorine on either side. And draw the rough skeleton structure for the Lewis structure of NOCl something like this:

Also read: How to draw Lewis structure of CH₃COOH (5 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since nitrogen is surrounded by oxygen and chlorine, use four electrons to show two chemical bonds as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 18 valence electrons. And in the above structure, we have already used four valence electrons. Hence, fourteen valence electrons are remaining.

Two valence electrons represent one lone pair. So fourteen valence electrons = seven lone pairs.

Note that both (nitrogen 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 chlorine, so oxygen and chlorine will get three lone pairs. And the central atom (nitrogen) will get one lone pair.

So the Lewis structure of NOCl looks something like this:

In the above structure, you can see that the octet is completed on outside atoms. But, the central atom (nitrogen) 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 ClO^– (4 steps)

#4 Complete octet on central atom

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

Now nitrogen already has six valence electrons. Hence, nitrogen 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 nitrogen atom. And then, the Lewis structure of NOCl looks something like this:

Here, the lone pair of oxygen is converted (instead of chlorine). But chlorine is less electronegative than oxygen, so why not the lone pair of chlorine is converted?

This is because… we do not get the formal charges on atoms closer to zero, if we convert the lone pair of chlorine.

In the above structure, you can see that the octet is completed on the central atom (nitrogen), 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 Cl₂O (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 nitrogen atom

Valence electrons = 5
Nonbonding electrons = 2
Bonding electrons = 6

Formal charge = 5 – 2 – ½ (6) = 0

• For oxygen atom

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

Formal charge = 6 – 4 – ½ (4) = 0

• For 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 NOCl 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 NOCl.

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

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Related

• Lewis structure of CH₃COOH
• Lewis structure of ClO^–
• Lewis structure of Cl₂O
• Lewis structure of ClO₄^–
• Lewis structure of CBr₄

External video

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

External links

• NOCl Lewis Structure, Molecular Geometry, Hybridization, and Polarity – Techiescientist
• What is the Lewis structure of “nitrosyl chloride”, NOCl? – Socratic
• NOCl Lewis structure, molecular geometry, bond angle, hybridization – Topblogtenz
• Chemical Bonding: NOCl Lewis Structure – The Geoexchange
• Nitrosyl Chloride, NOCl Molecular Geometry & Polarity – Tutor-Homework.com
• NOCl Lewis Structure in 6 Steps (With Images) – Pediabay
• NOCl Lewis structure, Molecular Geometry, Shape and Hybridization – Geometry of Molecules
• Determine the number of nonbonding electron pairs on the central atom of NOCl (lewis structure) – Wyzant
• Draw the Lewis structure for NOCl. Give the number of electrons in each species – Homework.Study.com
• Draw the Lewis structure of NOCl, nitrosyl chloride – Chegg
• NOCl Lewis Structure (Nitrosyl Chloride) – Pinterest
• VSEPR shape of NOCl:Biochemhelp – AceOrganicChem
• Why is N the central atom for NOCl? – Quora
• Draw the Lewis dot structure for NOCl – Quizlet
• Consider the Lewis structure of nitrosyl chloride (NOCl) – Course Hero