# SCl4 Lewis Structure

SCl4 (sulfur tetrachloride) has one sulfur atom and four chlorine atoms. In the lewis structure of SCl4, there are three single bonds around the sulfur atom, with three chlorine atoms attached to it. Each chlorine atom has three lone pairs, and the sulfur atom has one lone pair.

## Steps

Here’s how you can draw the SCl4 lewis structure step by step.

Step #1: draw sketch
Step #2: mark lone pairs
Step #3: mark charges (if there are)

Let’s break down each step in detail.

### #1 Draw Sketch

• First, determine the total number of valence electrons

In the periodic table, sulfur lies in group 16, and chlorine lies in group 17.

Hence, sulfur has six valence electrons and chlorine has seven valence electrons.

Since SCl4 has one sulfur atom and four chlorine atoms, so…

Valence electrons of one sulfur atom = 6 × 1 = 6
Valence electrons of four chlorine atoms = 7 × 4 = 28

And the total valence electrons = 6 + 28 = 34

• Second, find the total electron pairs

We have a total of 34 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 = 34 ÷ 2 = 17

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

### #2 Mark Lone Pairs

Here, we have a total of 17 electron pairs. And four S — Cl bonds are already marked. So we have to only mark the remaining thirteen electron pairs as lone pairs on the sketch.

Also remember that both (sulfur and chlorine) are the period 3 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 chlorines.

So for each chlorine, there are three lone pairs, and for sulfur, there is one lone pair.

Mark the lone pairs on the sketch as follows:

### #3 Mark Charges

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

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

For sulfur atom, formal charge = 6 – 2 – ½ (8) = 0

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

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

And in the above structure, you can see that the central atom (sulfur) forms an octet. Hence, the octet rule is satisfied.

Therefore, this structure is the stable lewis structure of SCl4.