Lewis Structure of SiF4 (With 6 Simple Steps to Draw!)

Ready to learn how to draw the lewis structure of SiF4?

Awesome!

Here, I have explained 6 simple steps to draw the lewis dot structure of SiF4 (along with images).

So, if you are ready to go with these 6 simple steps, then let’s dive right into it!

Lewis structure of SiF4 contains four single bonds between the Silicon (Si) atom and each Fluorine (F) atom. The Silicon atom (Si) is at the center and it is surrounded by 4 Fluorine atoms (F). The Silicon atom does not have a lone pair while all four fluorine atoms have three lone pairs each.

Let’s draw and understand this lewis dot structure step by step.

(Note: Take a pen and paper with you and try to draw this lewis structure along with me. I am sure you will definitely learn how to draw lewis structure of SiF4).

6 Steps to Draw the Lewis Structure of SiF4

Step #1: Calculate the total number of valence electrons

Here, the given molecule is SiF4 (silicon tetrafluoride). In order to draw the lewis structure of SiF4, first of all you have to find the total number of valence electrons present in the SiF4 molecule.
(Valence electrons are the number of electrons present in the outermost shell of an atom).

So, let’s calculate this first.

Calculation of valence electrons in SiF4

• For Silicon: 

Silicon is a group 14 element on the periodic table. ^[1]

Hence, the valence electrons present in silicon is 4 (see below image).

• For Fluorine: 

Fluorine is a group 17 element on the periodic table. ^[2]

Hence, the valence electrons present in fluorine is 7 (see below image).

Hence in a SiF4 molecule, 

Valence electrons given by Silicon (Si) atom = 4
Valence electrons given by each Fluorine (F) atom = 7
So, total number of Valence electrons in SiF4 molecule = 4 + 7(4) = 32

Step #2: Select the center atom

While selecting the center atom, always put the least electronegative atom at the center.

(Remember: Fluorine is the most electronegative element on the periodic table and the electronegativity decreases as we move right to left in the periodic table as well as top to bottom in the periodic table). ^[3]

Here in the SiF4 molecule, if we compare the silicon atom (Si) and fluorine atom (F), then silicon is less electronegative than fluorine.

So, silicon should be placed in the center and the remaining 4 fluorine atoms will surround it.

Step #3: Put two electrons between the atoms to represent a chemical bond

Now in the above sketch of SiF4 molecule, put the two electrons (i.e electron pair) between each silicon atom and fluorine atom to represent a chemical bond between them.

These pairs of electrons present between the Silicon (Si) and Fluorine (F) atoms form a chemical bond, which bonds the silicon and fluorine atoms with each other in a SiF4 molecule.

Step #4: Complete the octet (or duplet) on outside atoms. If the valence electrons are left, then put the valence electrons pair on the central atom

Don’t worry, I’ll explain!

In the Lewis structure of SiF4, the outer atoms are fluorine atoms.

So now, you have to complete the octet on these fluorine atoms (because fluorine requires 8 electrons to have a complete outer shell).

Now, you can see in the above image that all the fluorine atoms form an octet.

Also, all the 32 valence electrons of SiF4 molecule (as calculated in step #1) are used in the above structure. So there are no remaining electron pairs.

Hence there is no change in the above sketch of SiF4.

Let’s move to the next step.

Step #5: Check whether the central atom has octet or not. If it does not have an octet, then move the electron pair from the outer atom to form a double bond or triple bond

In this step, we have to check whether the central atom (i.e silicon) has an octet or not. 

In simple words, we have to check whether the central Silicon (Si) atom is having 8 electrons or not.

As you can see from the above image, the central atom (i.e silicon), has 8 electrons. So it fulfills the octet rule and the silicon atom is stable.

Step #6: Check the stability of lewis structure by calculating the formal charge on each atom

Now, you have come to the final step and here you have to check the formal charge on silicon atom (Si) as well as each fluorine atom (F).

For that, you need to remember the formula of formal charge;

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

• For Silicon:
  Valence electrons = 4 (as it is in group 14)
  Nonbonding electrons = 0
  Bonding electrons = 8
• For Fluorine:
  Valence electron = 7 (as it is in group 17)
  Nonbonding electrons = 6
  Bonding electrons = 2

Formal charge	=	Valence electrons	–	Nonbonding electrons	–	(Bonding electrons)/2
Si	=	4	–	0	–	8/2	=	0
F	=	7	–	6	–	2/2	=	0

So you can see above that the formal charges on silicon as well as fluorine are “zero”.

Hence, there will not be any change in the above structure and the above lewis structure of SiF4 is the final stable structure only.

Each electron pair (:) in the lewis dot structure of SiF4 represents the single bond ( | ). So the above lewis dot structure of SiF4 can also be represented as shown below.

Related lewis structures for your practice:
Lewis structure of CH3F
Lewis structure of NH4+
Lewis structure of NH2-
Lewis structure of AlCl3
Lewis structure of BeH2

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