NOCl Lewis structure

NOCl (nitrosyl chloride) has one nitrogen atom, one oxygen atom, and one chlorine atom.

In the NOCl Lewis structure, there is a double bond between nitrogen and oxygen atom, and a single bond between nitrogen and chlorine atom. The nitrogen atom has one lone pair, the oxygen atom has two lone pairs, and the chlorine atom has three lone pairs.

Alternative method: Lewis structure of NOCl

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, nitrogen lies in group 15, oxygen lies in group 16, and chlorine lies in group 17.

Hence, nitrogen has five valence electrons, oxygen has six valence electrons, and chlorine has seven valence electrons.

Since NOCl has one nitrogen atom, one oxygen atom, and one chlorine atom, so…

Valence electrons of one nitrogen atom = 5 × 1 = 5
Valence electrons of one oxygen atom = 6 × 1 = 6
Valence electrons of one chlorine atom = 7 × 1 = 7

And the total valence electrons = 5 + 6 + 7 = 18

Learn how to find: Nitrogen valence electrons, Oxygen valence electrons, and Chlorine valence electrons

• Second, find the total electron pairs

We have a total of 18 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 18 ÷ 2 = 9

• Third, determine the central atom

We have to place the least electronegative atom at the center.

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

Therefore, place nitrogen in the center and oxygen and chlorine on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 9 electron pairs. And two bonds are already marked. So we have to only mark the remaining seven electron pairs as lone pairs on the sketch.

Also remember 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.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are oxygen and chlorine.

So for oxygen and chlorine, there are three lone pairs, and for nitrogen, there is one lone pair.

Mark the lone pairs on the sketch as follows:

Formal charge

Use the following formula to calculate the formal charges on atoms:

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

For nitrogen atom, formal charge = 5 – 2 – ½ (4) = +1

For oxygen atom, formal charge = 6 – 6 – ½ (2) = -1

For chlorine atom, formal charge = 7 – 6 – ½ (2) = 0

Here, both nitrogen and oxygen atoms have charges, so mark them on the sketch as follows:

The above structure is not a stable Lewis structure because both nitrogen and oxygen atoms have charges. Therefore, reduce the charges (as below) by converting lone pairs to bonds.

Convert a lone pair of the oxygen atom to make a new N — O bond with the nitrogen atom as follows:

Final structure

The final structure of NOCl features a central nitrogen atom connected to an oxygen atom via a double covalent bond and to a chlorine atom through a single covalent bond. In this layout, the nitrogen atom satisfies the octet rule by forming three total bonds and retaining one lone pair. The oxygen atom fulfills its octet by maintaining two lone pairs, while the chlorine atom completes its octet by keeping three lone pairs of its own. This setup is the most stable because it results in formal charges of zero for all participating atoms, representing the most energetically favorable state for the molecule. Consequently, this specific electronic distribution serves as the definitive and most accurate Lewis representation of nitrosyl chloride.

Next: SeO₂ Lewis structure

External video

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

External links

• https://techiescientist.com/nocl-lewis-structure/
• https://geometryofmolecules.com/nocl-lewis-structure-molecular-geometry-shape-and-hybridization/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/NOCl-lewis-structure.html
• https://lambdageeks.com/nocl-lewis-structure/
• https://socratic.org/questions/5a15940211ef6b6236996109