SF6 (Sulfur hexafluoride) Lewis Structure

SF6 (Sulfur hexafluoride) molecule contains one sulfur atom and six fluorine atoms. Lewis structure of SF6 is given below. In SF6 lewis structure, each fluorine atom has made single bonds with center sulfur atom. There are no lone pairs on sulfur atom and three lone pairs on each fluorine atom. In this tutorial, we will learn how to draw the lewis structure of SF4 step by step by covering all theories.


SF6 lewis structure

SF6 lewis structure

In this lewis structure of SF6, center sulfur atom has made six sigma bonds with six fluorine atoms. Each fluorine atom has three lone pairs. Because, there are 6 sigma bonds around sulfur atom, there are 12 electrons in sulfur's valence shell. It is a another example that sulfur can keep more than 8 electrons in its last shell. Also, there are no charges on atoms in SF6 lewis structure and no overall charge in the molecule.



Steps of drawing lewis structure of SF6 using VSEPR theory

There are general steps to draw a lewis structure of a molecule. Number of steps can be changed according the complexity of the given molecule or ion. Now, we are going to study each step of drawing the lewis structure of SF6.



  1. Find total number of electrons of the valance shells of sulfur and fluorine atoms
  2. Total electrons pairs existing as lone pairs and bonds
  3. Center atom selection
  4. Mark lone pairs on atoms
  5. Mark charges on atoms if there are charges
  6. Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain best lewis structure.

Determining total number of electrons of the valance shells of SF6

There are only two elements in sulfur hexafluoride; sulfur and fluorine. Sulfur is a group VIA element in the periodic table and has six electrons in its last shell (valence shell). Fluorine is a group VIIA element in the periodic table and contains seven electrons in its last shell.


  • valence electrons given by sulfur atom = 6 * 1 = 6
  • valence electrons given by fluorine atoms = 7 * 6 = 42

  • Total valence electrons = 6 + 42 = 48

Total valence electrons pairs

Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells

Total electron pairs are determined by dividing the number total valence electrons by two. For, SF6, Total pairs of electrons are 24 (48/2) in their valence shells.




Selection of center atom of SF6

There are requirements to be the center atom in a molecule. Having a high valence and being the most electropositive atom are the most important facts to be the center atom. In SF6, there are only two elements to select the center atom and we are going to check those requirements to select the center atom and basic sketch of the molecule.


  1. Maximum valence: Sulfur's maximum valence is 6. Fluorine's maximum valence is 1. From that fact, Sulfur has the high priority to be the center atom.
  2. Most electropositive element: Sulfur's and fluorine's electronegativity values are 2.5 and 4.0 respectively. in this case, sulfur is more electropositive than fluorine. In this occasion too, sulfur has the highest chance to be the center atom.
  3. From above 1 and 2 facts, it is clear that sulfur atom should be the center atom.
sketch of SF6

Mark lone pairs on atoms of SF6

After determining the center atom and sketch of SF6 molecule, we can start to mark lone pairs on atoms. Remember that, there are total of 24 electron pairs to mark as bonds and lone pairs in SF6 molecule.

  • There are already 6 sigma bonds in the above drawn sketch (6 S-F bonds). Now only 18 (24-6=18) lone pairs are remaining to mark on sulfur and fluorine atoms.
  • Usually, those remaining electron pairs should be started to mark on outside atoms (in this case on fluorine atoms). Then, mark lone pairs on fluorine atoms. Each outside fluorine atom will take 3 lone pairs. Now, 18 electron pairs are marked as lone pairs on outside fluorine atoms. So, all lone pairs were marked and there are no more lone pairs to mark on sulfur atom.
mark lone pairs on sulfur and fluorine atoms SF6 lewis structure

Mark charges on atoms and reduce charges to obtain most stable lewis structure

According to the above structure, there are no charges on any of atoms in our structure of SF6. Therefore, we don't need to reduce charges to get the most stable structure. That means, we have already obtained the lewis structure of SF6.




Questions




the number of electrons in the valence shell of sulphur in sf6 is

There are six sigma bonds and no lone pairs around sulphur atom. In six sigma bonds, there are twelve electrons. Therefore, there are twelve electrons in the valence shell of sulphur in SF6.



How many lone pairs are there in SF6 lewis structures?

All six electrons in valence shell of sulfur is shared with fluorine atoms to make bonds. Therefore, there are no lone pairs on sulfur atom. Each fluorine atom give one electron to make a bond with sulfur atom. There were 7 electrons in a fluorine atom. Therefore, each fluorine atom has 3 lone pairs.






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Lewis Structures of Molecules

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