SF6 Lewis structure

SF₆ (sulfur hexafluoride) has one sulfur atom and six fluorine atoms.

In the SF₆ Lewis structure, there are six single bonds around the sulfur atom, with six fluorine atoms attached to it, and on each fluorine atom, there are three lone pairs.

Alternative method: Lewis structure of SF₆

Rough sketch

• First, determine the total number of valence electrons

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

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

Since SF₆ has one sulfur atom and six fluorine atoms, so…

Valence electrons of one sulfur atom = 6 × 1 = 6
Valence electrons of six fluorine atoms = 7 × 6 = 42

And the total valence electrons = 6 + 42 = 48

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

• Second, find the total electron pairs

We have a total of 48 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 = 48 ÷ 2 = 24

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 24 electron pairs. And six S — F bonds are already marked. So we have to only mark the remaining eighteen 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 fluorine 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 fluorines.

So for each fluorine, there are three lone pairs, and for sulfur, there is zero lone pair because all eighteen 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 (12) = 0

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

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

Final structure

The final structure of SF₆ involves a central sulfur atom connected to six fluorine atoms through single covalent bonds. In this arrangement, the sulfur atom utilizes an expanded octet to accommodate twelve valence electrons across six bonding pairs. Each fluorine atom fulfills its octet by maintaining three lone pairs of its own alongside the single shared bond. This configuration is the most stable because it results in formal charges of zero for all atoms involved, representing the most energetically favorable state for the molecule. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of sulfur hexafluoride.

Next: PH₃ Lewis structure

External video

• SF6 Lewis Structure: How to Draw the Lewis Structure for SF6 – YouTube • Wayne Breslyn

External links

• https://www.chemistryscl.com/general/SF6-lewis-structure/
• https://geometryofmolecules.com/sf6-lewis-structure-shape-and-polarity/
• https://techiescientist.com/sf6-lewis-structure/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/SF6-lewis-structure.html
• https://topblogtenz.com/sf6-lewis-structure-molecular-geometry-shape-bond-angle-hybridization/
• https://lambdageeks.com/sf6-lewis-structure/