SO2Cl2 (sulfuryl chloride) has one sulfur atom, two oxygen atoms, and two chlorine atoms. In the lewis structure of SO2Cl2, there are two single bonds and two double bonds around the sulfur atom, with two chlorine atoms and two oxygen atoms attached to it. Each chlorine atom has three lone pairs, and each oxygen atom has two lone pairs.
Here’s how you can draw the SO2Cl2 lewis structure step by step.
Step #1: draw sketch
Step #2: mark lone pairs
Step #3: mark charges
Step #4: minimize charges
Step #5: minimize charges again (if there are)
Let’s break down each step in detail.
#1 Draw Sketch
- First, determine the total number of valence electrons
Hence, both sulfur and oxygen have six valence electrons, and chlorine has seven valence electrons.
Since SO2Cl2 has one sulfur atom, two oxygen atoms, and two chlorine atoms, so…
Valence electrons of one sulfur atom = 6 × 1 = 6
Valence electrons of two oxygen atoms = 6 × 2 = 12
Valence electrons of two chlorine atoms = 7 × 2 = 14
And the total valence electrons = 6 + 12 + 14 = 32
- Second, find the total electron pairs
We have a total of 32 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 = 32 ÷ 2 = 16
- Third, determine the central atom
We have to place the least electronegative atom at the center.
Since sulfur is less electronegative than oxygen and chlorine, assume that the central atom is sulfur.
Therefore, place sulfur in the center and oxygen and chlorine on either side.
- And finally, draw the rough sketch
#2 Mark Lone Pairs
Here, we have a total of 16 electron pairs. And four bonds are already marked. So we have to only mark the remaining twelve 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. And oxygen 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 oxygens and chlorines.
So for each oxygen and each chlorine, there are three lone pairs, and for sulfur, there is zero lone pair because all twelve electron pairs are over.
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 – 0 – ½ (8) = +2
For each oxygen atom, formal charge = 6 – 6 – ½ (2) = -1
For each chlorine atom, formal charge = 7 – 6 – ½ (2) = 0
Here, both sulfur and oxygen atoms have charges, so mark them on the sketch as follows:
The above structure is not a stable lewis structure because both sulfur and oxygen atoms have charges. Therefore, reduce the charges (as below) by converting lone pairs to bonds.
#4 Minimize Charges
Convert a lone pair of the oxygen atom to make a new S — O bond with the sulfur atom as follows:
#5 Minimize Charges Again
Since there are charges on sulfur and oxygen atoms, again convert a lone pair of the oxygen atom to make a new S — O bond with the sulfur atom as follows:
In the above structure, you can see that the central atom (sulfur) forms an octet. Hence, the octet rule is satisfied.
Also, the above structure is more stable than the previous structures. Therefore, this structure is the stable lewis structure of SO2Cl2.
Next: Lewis Structure of ClO2