Lewis structure of SOCl2

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The Lewis structure of SOCl₂ contains one double bond and two single bonds, with sulfur in the center, and oxygen and two chlorines on either side. There are three lone pairs on each chlorine atom, two lone pairs on the oxygen atom, and one lone pair on the sulfur atom.

Steps

By using the following steps, you can easily draw the Lewis structure of SOCl₂.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)
#5 Convert lone pair and calculate formal charge again (if formal charges are not closer to zero)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… both sulfur and oxygen are the group 16 elements, and chlorine is a group 17 element. Hence, both sulfur and oxygen have six valence electrons, and chlorine has seven valence electrons.

Now SOCl₂ has one sulfur atom, one oxygen atom, and two chlorine atoms.

So the total number of valence electrons = valence electrons of sulfur atom + valence electrons of oxygen atom + (valence electrons of chlorine atom × 2)

Therefore, the total number of valence electrons = 6 + 6 + 14 = 26

• Now decide the central atom

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for sulfur, oxygen, and chlorine as follows:

Electronegativity value of sulfur = 2.58
Electronegativity value of oxygen = 3.44
Electronegativity value of chlorine = 3.16

Obviously, sulfur is less electronegative than oxygen and chlorine. Hence, assume that sulfur is the central atom.

So now, put sulfur in the center and oxygen and two chlorines on either side. And draw the rough skeleton structure for the Lewis structure of SOCl₂ something like this:

Also read: How to draw Lewis structure of ICl (5 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since sulfur is surrounded by oxygen and two chlorines, use six electrons to show three chemical bonds as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 26 valence electrons. And in the above structure, we have already used six valence electrons. Hence, twenty valence electrons are remaining.

Two valence electrons represent one lone pair. So twenty valence electrons = ten lone pairs.

Note 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.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are oxygen and two chlorines, so oxygen and two chlorines will get three lone pairs. And the central atom (sulfur) will get one lone pair.

So the Lewis structure of SOCl₂ looks something like this:

In the above structure, you can see that the octet is completed on the central atom (sulfur), and also on the outside atoms. Therefore, the octet rule is satisfied.

Now calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of SO₂Cl₂ (5 steps)

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

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

Collect the data from the above structure and then, write it down below as follows:

• For sulfur atom

Valence electrons = 6
Nonbonding electrons = 2
Bonding electrons = 6

Formal charge = 6 – 2 – ½ (6) = +1

• For oxygen atom

Valence electrons = 6
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 6 – 6 – ½ (2) = -1

• For each chlorine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of SOCl₂ looks something like this:

In the above structure, you can see that the formal charges of atoms are not closer to zero. Therefore, convert lone pair and calculate formal charge again.

Also read: How to draw Lewis structure of C₄H₁₀ (3 steps)

#5 Convert lone pair and calculate formal charge again

As mentioned earlier, sulfur is a period 3 element, so it can keep more than 8 electrons in its last shell.

So convert one lone pair from the oxygen atom to make a new bond with the sulfur atom. And then, the Lewis structure of SOCl₂ looks something like this:

Now one last thing we need to do is, calculate the formal charge again and check the stability of the above structure.

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

Collect the data from the above structure and then, write it down below as follows:

• For sulfur atom

Valence electrons = 6
Nonbonding electrons = 2
Bonding electrons = 8

Formal charge = 6 – 2 – ½ (8) = 0

• For oxygen atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 0

• For each chlorine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of SOCl₂ looks something like this:

In the above structure, you can see that the formal charges of all atoms are zero. Therefore, this is the stable Lewis structure of SOCl₂.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

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Related

• Lewis structure of ICl
• Lewis structure of SO₂Cl₂
• Lewis structure of C₄H₁₀
• ClO₂ Lewis structure
• Lewis structure of SCl₄

External links

• SOCl2 Lewis Structure in 6 Steps (With Images) – Pediabay
• SOCl2 lewis structure, Molecular geometry, Polar or non polar, Bond angle – Topblogtenz
• Chemical Bonding: SOCl2 Lewis Structure – The Geoexchange
• Draw the Lewis dot structure for SOCl2 – Homework.Study.com
• Lewis structure of Cl2SO – Chemistry Stack Exchange
• Draw a Lewis structure for SOCl2 – Chegg
• Write a Lewis structure that obeys the octet rule for SOCl2 (S is the central atom) and assign formal charges to each atom – Brainly
• SOCl2 Geometry and Hybridization – Chemistry Steps
• What is SOCl2 molecular geometry? – Quora
• Lewis structure of the compound thionyl chloride (SOCl2) – Bartleby
• Draw the Lewis structure for SOCl2 (sulfur bonded to two Cl and one O) – Numerade
• Write the Lewis dot structure for SOCl2 – Quizlet