BrCl3 Lewis structure

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BrCl3 Lewis Structure
BrCl3 Lewis structure

BrCl3 (bromine trichloride) has one bromine atom and three chlorine atoms.

In the BrCl3 Lewis structure, there are three single bonds around the bromine atom, with three chlorine atoms attached to it. Each chlorine atom has three lone pairs, and the bromine atom has two lone pairs.


Here’s how you can easily draw the BrCl3 Lewis structure step by step:

#1 Draw a rough skeleton structure
#2 Mention lone pairs on the atoms
#3 If needed, mention formal charges on the atoms

Now, let’s take a closer look at each step mentioned above.

#1 Draw a rough skeleton structure

  • First, determine the total number of valence electrons
Periodic table

In the periodic table, both bromine and chlorine lie in group 17.

Hence, both bromine and chlorine have seven valence electrons.

Since BrCl3 has one bromine atom and three chlorine atoms, so…

Valence electrons of one bromine atom = 7 × 1 = 7
Valence electrons of three chlorine atoms = 7 × 3 = 21

And the total valence electrons = 7 + 21 = 28

Learn how to find: Bromine valence electrons and Chlorine valence electrons

  • Second, find the total electron pairs

We have a total of 28 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 = 28 ÷ 2 = 14

  • Third, determine the central atom

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

Since bromine is less electronegative than chlorine, assume that the central atom is bromine.

Therefore, place bromine in the center and chlorines on either side.

  • And finally, draw the rough sketch
BrCl3 Lewis Structure (Step 1)
Rough sketch of BrCl3 Lewis structure

#2 Mention lone pairs on the atoms

Here, we have a total of 14 electron pairs. And three Br — Cl bonds are already marked. So we have to only mark the remaining eleven electron pairs as lone pairs on the sketch.

Also remember that bromine is a period 4 element, so it can keep more than 8 electrons in its 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 chlorines.

So for each chlorine, there are three lone pairs, and for bromine, there are two lone pairs.

Mark the lone pairs on the sketch as follows:

BrCl3 Lewis Structure (Step 2)
Lone pairs marked, and got the stable Lewis structure of BrCl3

#3 If needed, mention formal charges on the atoms

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

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

For bromine atom, formal charge = 7 – 4 – ½ (6) = 0

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

Here, both bromine and chlorine atoms do not have charges, so no need to mark the charges.

In the above structure, you can see that the central atom (bromine) forms an octet. And the outside atoms (chlorines) also form an octet. Hence, the octet rule is satisfied.

Therefore, this structure is the stable Lewis structure of BrCl3.

Next: NO2Cl Lewis structure

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