SOF4 Lewis structure

SOF₄ (sulfur tetrafluoride oxide) has one sulfur atom, one oxygen atom, and four fluorine atoms.

In SOF₄ Lewis structure, there is one double bond and four single bonds around the sulfur atom, with one oxygen atom and four fluorine atoms attached to it. Each fluorine atom has three lone pairs, and the oxygen atom has two lone pairs.

Alternative method: Lewis structure of SOF₄

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, both sulfur and oxygen lie in group 16, and fluorine lies in group 17.

Hence, both sulfur and oxygen have six valence electrons, and fluorine has seven valence electrons.

Since SOF₄ has one sulfur atom, one oxygen atom, and four fluorine atoms, so…

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

And the total valence electrons = 6 + 6 + 28 = 40

Learn how to find: Sulfur valence electrons, Oxygen valence electrons, and Fluorine valence electrons

• Second, find the total electron pairs

We have a total of 40 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 = 40 ÷ 2 = 20

• Third, determine the central atom

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

Since sulfur is less electronegative than oxygen and fluorine, assume that the central atom is sulfur.

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 20 electron pairs. And five bonds are already marked. So we have to only mark the remaining fifteen electron pairs as lone pairs on the sketch.

Also remember that sulfur is a period 3 element, so it can keep more than 8 electrons in its last shell. And both (oxygen and fluorine) are the period 2 elements, so they can not keep more than 8 electrons in their last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are oxygen and fluorines.

So for oxygen and each fluorine, there are three lone pairs, and for sulfur, there is zero lone pair because all fifteen electron pairs are over.

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 sulfur atom, formal charge = 6 – 0 – ½ (10) = +1

For oxygen atom, formal charge = 6 – 6 – ½ (2) = -1

For each fluorine 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.

Convert a lone pair of the oxygen atom to make a new S — O bond with the sulfur atom as follows:

Final structure

The final structure of SOF₄ comprises a central sulfur atom linked to four fluorine atoms and one oxygen atom. In this configuration, the sulfur atom utilizes an expanded valence shell to form six total bonds—a double covalent bond with the oxygen atom and four single covalent bonds with the fluorine atoms—with no lone pairs remaining on the sulfur. Within this layout, the oxygen atom fulfills its octet by maintaining two lone pairs, while each fluorine atom reaches a stable octet by retaining three lone pairs. This arrangement represents the most stable state for the molecule because it results in a formal charge of zero for every atom involved. Therefore, this specific electronic distribution serves as the definitive and most accurate Lewis representation of thionyl tetrafluoride.

Next: ClF₂^– Lewis structure

External video

• Lewis dot structure for OSF4 (and Molecular Geometry) – YouTube • Wayne Breslyn

External links

• https://lambdageeks.com/sof4-lewis-structure/
• https://www.bartleby.com/questions-and-answers/draw-the-lewis-for-structure-for-sof-4-including-all-the-lone-pair-electrons.-use-solid-and-dashed-t/6523b345-a829-41b5-b88e-54a634711f71
• https://homework.study.com/explanation/draw-a-lewis-dot-structure-for-sof-4.html
• https://www.chegg.com/homework-help/questions-and-answers/draw-best-lewis-structure-sof4-s-central-atom-total-number-lone-pairs-structure-enter-numb-q49798507