Cl3- Lewis structure

Cl₃^– has three chlorine atoms.

In Cl₃^– Lewis structure, there are two single bonds around the chlorine atom, with two other chlorine atoms attached to it, and on each chlorine atom, there are three lone pairs.

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

Alternative method: Lewis structure of Cl₃^–

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, chlorine lies in group 17. Hence, chlorine has seven valence electrons.

Since Cl₃^– has three chlorine atoms, so…

Valence electrons of three chlorine atoms = 7 × 3 = 21

Now the Cl₃^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 21 + 1 = 22

Learn how to find: Chlorine 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

Here, there are three atoms and all atoms are chlorine, so we can assume any one as the central atom.

Let’s assume that the central atom is center chlorine.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 11 electron pairs. And two Cl — Cl bonds are already marked. So we have to only mark the remaining nine electron pairs as lone pairs on the sketch.

Also remember that 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 left chlorine and right chlorine.

So for each chlorine, 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 left chlorine and right chlorine atom, formal charge = 7 – 6 – ½ (2) = 0

For center chlorine atom, formal charge = 7 – 6 – ½ (4) = -1

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

Final structure

The final structure of Cl₃^– consists of a central chlorine atom linked to two terminal chlorine atoms through single covalent bonds. In this configuration, the central chlorine atom utilizes an expanded valence shell to accommodate ten electrons, which consist of two bonding pairs and three lone pairs. Within this layout, each of the two terminal chlorine atoms successfully satisfies the octet rule by maintaining three lone pairs alongside its single shared bond. This arrangement represents the most stable state for the ion because the negative formal charge is localized on the central chlorine atom, while the terminal chlorine atoms maintain a formal charge of zero. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of Cl₃^–.

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: PCl₂^– Lewis structure

External video

• How to Draw the Lewis Structure for Cl3 – – YouTube • Wayne Breslyn

External links

• https://socratic.org/questions/what-is-the-lewis-structure-of-cl-3
• https://homework.study.com/explanation/draw-the-best-lewis-structure-for-cl3-1-what-is-the-formal-charge-on-the-cl.html
• https://brainly.com/question/11628954
• https://www.chegg.com/homework-help/questions-and-answers/22-draw-best-lewis-structure-cl3-formal-charge-central-cl-atom-1-b-0-c-1-d-2-e-2-23-draw-b-q37864532
• https://www.coursehero.com/tutors-problems/Chemistry/30934243-Draw-the-best-Lewis-structure-for-Cl3-and-determinethe-formal-charge-o/