BrCl4- Lewis structure

BrCl₄^– has one bromine atom and four chlorine atoms.

In BrCl₄^– Lewis structure, there are four single bonds around the bromine atom, with four chlorine atoms attached to it. Each chlorine atom has three lone pairs, and the bromine atom has two lone pairs.

Also, there is a negative (-1) charge on the bromine atom.

Alternative method: Lewis structure of BrCl₄^–

Rough sketch

• First, determine the total number of valence electrons

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

Hence, both bromine and chlorine have seven valence electrons.

Since BrCl₄^– has one bromine atom and four chlorine atoms, so…

Valence electrons of one bromine atom = 7 × 1 = 7
Valence electrons of four chlorine atoms = 7 × 4 = 28

Now the BrCl₄^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 7 + 28 + 1 = 36

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

• Second, find the total electron pairs

We have a total of 36 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 = 36 ÷ 2 = 18

• 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

Lone pair

Here, we have a total of 18 electron pairs. And four Br — Cl bonds are already marked. So we have to only mark the remaining fourteen 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:

Formal charge

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 (8) = -1

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

Here, the bromine atom has a charge, so mark it on the sketch as follows:

Final structure

The final structure of BrCl₄^– includes a central bromine atom linked to four chlorine atoms through single covalent bonds. In this arrangement, the bromine atom utilizes an expanded valence shell to accommodate twelve electrons, forming four bonding pairs and retaining two lone pairs. Within this layout, each of the four chlorine atoms successfully reaches a stable octet by maintaining three lone pairs alongside its single shared bond. This configuration represents the most stable state for the ion because it minimizes formal charges across the structure, with the negative formal charge residing on the central bromine atom. Thus, this specific electronic distribution serves as the definitive and most accurate Lewis representation of BrCl₄^–.

To properly represent this as a polyatomic ion, the entire Lewis structure is enclosed within square brackets. The overall charge of 1- is then written as a superscript outside the brackets at the top right, indicating that the structure possesses one additional electron beyond the valence count of the neutral atoms.

Next: XeO₂ Lewis structure

External video

• How to Draw the Lewis Dot Structure for BrCl4 – – YouTube • Wayne Breslyn

External links

• https://lambdageeks.com/brcl4-lewis-structure/
• https://homework.study.com/explanation/predict-the-electron-pair-geometry-and-the-molecular-structure-of-brcl4.html
• https://www.numerade.com/ask/question/draw-the-best-lewis-dot-structure-for-brcl4-what-is-the-geometry-of-the-structure-draw-or-namewhat-types-of-bonds-are-between-each-atom-is-the-molecule-polar-or-non-polar-what-are-the-formal-17033/
• https://www.chegg.com/homework-help/questions-and-answers/draw-lewis-structure-brcl-4–molecular-geometry-molecular-shape-hybridization-central-atom-q65008579
• https://brainly.com/question/29591896