SeBr2 Lewis structure

SeBr₂ (selenium dibromide) has one selenium atom and two bromine atoms.

In SeBr₂ Lewis structure, there are two single bonds around the selenium atom, with two bromine atoms attached to it. Each bromine atom has three lone pairs, and the selenium atom has two lone pairs.

Alternative method: Lewis structure of SeBr₂

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, selenium lies in group 16, and bromine lies in group 17.

Hence, selenium has six valence electrons and bromine has seven valence electrons.

Since SeBr₂ has one selenium atom and two bromine atoms, so…

Valence electrons of one selenium atom = 6 × 1 = 6
Valence electrons of two bromine atoms = 7 × 2 = 14

And the total valence electrons = 6 + 14 = 20

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

• Second, find the total electron pairs

We have a total of 20 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 = 20 ÷ 2 = 10

• Third, determine the central atom

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

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

Therefore, place selenium in the center and bromines on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 10 electron pairs. And two Se — Br bonds are already marked. So we have to only mark the remaining eight electron pairs as lone pairs on the sketch.

Also remember that both (selenium and bromine) are the period 4 elements, so they can keep more than 8 electrons in their last shell.

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

So for each bromine, there are three lone pairs, and for selenium, 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 selenium atom, formal charge = 6 – 4 – ½ (4) = 0

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

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

Final structure

The final structure of SeBr₂ contains a central selenium atom linked to two bromine atoms through single covalent bonds. In this layout, the selenium atom satisfies the octet rule by forming two bonding pairs and retaining two lone pairs. Within this arrangement, each bromine atom successfully reaches a stable octet by maintaining three lone pairs alongside its single shared bond. This configuration represents the most stable state for the molecule because it results in a formal charge of zero for every atom involved. Therefore, this specific electronic distribution serves as the definitive and most accurate Lewis representation of selenium dibromide.

Next: BF₂ Lewis structure

External video

• How to Draw the Lewis Dot Structure for SeBr2: Selenium dibromide – YouTube • Wayne Breslyn

External links

• https://www.chegg.com/homework-help/questions-and-answers/7-draw-lewis-structure-sebr2-molecule-total-number-valence-electrons-b-draw-structure-show-q47455647
• https://www.answers.com/Q/What_is_the_Lewis_structure_of_selenium_dibromide