SO2F2 Lewis Structure in 5 Steps (With Images)

So you have seen the above image by now, right?

Let me explain the above image in short.

SO2F2 lewis structure has a Sulfur atom (S) at the center which is surrounded by two Oxygen atoms (O) and two Fluorine atoms (F). There are single bonds between the Sulfur & Fluorine atoms and double bonds between the Sulfur & Oxygen atoms. There are 2 lone pairs on Oxygen atoms (O) and 3 lone pairs on Fluorine atoms (F).

If you haven’t understood anything from the above image of SO2F2 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of SO2F2 molecule.

So let’s move to the steps of drawing the lewis structure of SO2F2.

Steps of drawing SO2F2 lewis structure

Step 1: Find the total valence electrons in SO2F2 molecule

In order to find the total valence electrons in SO2F2 molecule, first of all you should know the valence electrons present in sulfur atom, oxygen atom as well as fluorine atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)

Here, I’ll tell you how you can easily find the valence electrons of sulfur, oxygen as well as fluorine using a periodic table.

Total valence electrons in SO2F2 molecule

→ Valence electrons given by sulfur atom:

Sulfur is a group 16 element on the periodic table. ^[1] Hence the valence electrons present in sulfur is 6.

You can see the 6 valence electrons present in the sulfur atom as shown in the above image.

→ Valence electrons given by oxygen atom:

Oxygen is group 16 element on the periodic table. ^[2] Hence the valence electrons present in oxygen is 6.

You can see the 6 valence electrons present in the oxygen atom as shown in the above image.

→ Valence electrons given by fluorine atom:

Fluorine is group 17 element on the periodic table. ^[3] Hence the valence electron present in fluorine is 7.

You can see the 7 valence electrons present in the fluorine atom as shown in the above image.

Hence, 

Total valence electrons in SO2F2 molecule = valence electrons given by 1 sulfur atom + valence electrons given by 2 oxygen atoms + valence electrons given by 2 fluorine atoms = 6 + 6(2) + 7(2) = 32.

Step 2: Select the central atom

For selecting the center atom, you have to remember that the atom which is less electronegative remains at the center.

Now here the given molecule is SO2F2 and it contains sulfur atom (S), oxygen atoms (O) and fluorine atoms (F).

You can see the electronegativity values of sulfur atom (S), oxygen atom (O) and fluorine atom (F) in the above periodic table.

If we compare the electronegativity values of sulfur (S), oxygen (O) and fluorine (F) then the sulfur atom is less electronegative.

So here the sulfur atom (S) is the center atom and the oxygen atoms (O) & fluorine atoms (F) are the outside atoms.

Step 3: Connect each atoms by putting an electron pair between them

Now in the SO2F2 molecule, you have to put the electron pairs between the sulfur-oxygen atoms and sulfur-fluorine atoms.

This indicates that these atoms are chemically bonded with each other in a SO2F2 molecule.

Step 4: Make the outer atoms stable

Now in this step, you have to check the stability of the outer atoms.

Here in the sketch of SO2F2 molecule, you can see that the outer atoms are oxygen atoms (O) and fluorine atoms (F).

These outer oxygen atoms and fluorine atoms are forming an octet and hence they are stable.

Also, in step 1 we have calculated the total number of valence electrons present in the SO2F2 molecule.

The SO2F2 molecule has a total 32 valence electrons and all these valence electrons are used in the above sketch.

Hence there are no remaining electron pairs to be kept on the central atom. 

So now let’s proceed to the next step.

Step 5: Check the stability of lewis structure

Now you have come to the final step in which you have to check the stability of lewis structure of SO2F2 molecule.

The stability of lewis structure can be checked by using a concept of formal charge.

In short, now you have to find the formal charge on sulfur (S) atom, oxygen (O) atoms as well as fluorine (F) atoms present in the SO2F2 molecule.

For calculating the formal charge, you have to use the following formula;

Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons

You can see the number of bonding electrons and nonbonding electrons for each atom of SO2F2 molecule in the image given below.

For Sulfur (S) atom:
Valence electrons = 6 (because sulfur is in group 16)
Bonding electrons = 8
Nonbonding electrons = 0

For Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 2
Nonbonding electrons = 6

For Fluorine (F) atom:
Valence electrons = 7 (because fluorine is in group 17)
Bonding electrons = 2
Nonbonding electrons = 6

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
S	=	6	–	8/2	–	0	=	+2
O	=	6	–	2/2	–	6	=	-1
F	=	7	–	2/2	–	6	=	0

From the above calculations of formal charge, you can see that the sulfur (S) atom has +2 charge while the two oxygen atoms have -1 charge.

So let’s keep these charges on the respective atoms of the SO2F2 molecule.

The above image shows that the lewis structure of SO2F2 is not stable.

So we have to minimize these charges by shifting the electron pair from the oxygen atom to the sulfur atom.

After shifting the electron pair from the oxygen atoms to the sulfur atom, the charges on sulfur and two oxygen atoms become zero. And this is a more stable lewis structure. (see below image).

In the above lewis dot structure of SO2F2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of SO2F2.

I hope you have completely understood all the above steps.

For more practice and better understanding, you can try other lewis structures listed below.

Try (or at least See) these lewis structures for better understanding:

PH2- Lewis Structure	NS2 Lewis Structure
SiH2O Lewis Structure	OF3- Lewis Structure
PH4+ Lewis Structure	SHF Lewis Structure