BrF2- Lewis structure

BrF₂^– has one bromine atom and two fluorine atoms.

In BrF₂^– Lewis structure, there are two single bonds around the bromine atom, with two fluorine atoms attached to it, and each atom has three lone pairs.

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

Alternative method: Lewis structure of BrF₂^–

Rough sketch

First, determine the total number of valence electrons

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

Hence, both bromine and fluorine have seven valence electrons.

Since BrF₂^– has one bromine atom and two fluorine atoms, so…

Valence electrons of one bromine atom = 7 × 1 = 7
Valence electrons of two fluorine atoms = 7 × 2 = 14

Now the BrF₂^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 7 + 14 + 1 = 22

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

• Second, find the total electron pairs

We have a total of 22 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 = 22 ÷ 2 = 11

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 11 electron pairs. And two Br — F bonds are already marked. So we have to only mark the remaining nine 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 fluorine is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are fluorines.

So for each atom, there are three 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 – 6 – ½ (4) = -1

For each fluorine 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 BrF₂^– includes a central bromine atom linked to two fluorine atoms through single covalent bonds. In this arrangement, the bromine atom utilizes an expanded valence shell to accommodate ten electrons, which consist of two bonding pairs and three lone pairs. Within this layout, each fluorine atom successfully satisfies the octet rule by maintaining three lone pairs alongside its single shared bond. This configuration represents the most stable state for the ion because the negative formal charge is localized on the central bromine atom, while both fluorine atoms retain a formal charge of zero. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of BrF₂^–.

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: C₂Cl₄ Lewis structure

External video

• How to Draw the Lewis Dot Structure for BrF2- – YouTube • Wayne Breslyn

External links

• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/BrF2-Lewis-structure.html
• https://lambdageeks.com/brf2-lewis-structure-2/
• https://homework.study.com/explanation/what-is-the-lewis-dot-structure-for-brf2.html
• https://www.chegg.com/homework-help/questions-and-answers/draw-lewis-structure-bromine-difluoride-brf2-ion-q31910730