Lewis Structure of SiO2 (With 6 Simple Steps to Draw!)

I’m super excited to teach you the lewis structure of SiO2 in just 6 simple steps.

Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of SiO2 molecule.

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

Lewis structure of SiO2 (or Silicon Dioxide) contains two double bonds between the Silicon (Si) atom and each Oxygen (O) atom. The Silicon atom (Si) is at the center and it is surrounded by 2 Oxygen atoms (O). The Silicon atom does not have a lone pair while both the Oxygen atoms have 2 lone pairs.

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 SiO2).

6 Steps to Draw the Lewis Structure of SiO2

Step #1: Calculate the total number of valence electrons

Here, the given molecule is SiO2 (silicon dioxide). In order to draw the lewis structure of SiO2, first of all you have to find the total number of valence electrons present in the SiO2 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 SiO2

• 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 Oxygen:

Oxygen is a group 16 element on the periodic table. ^[2]

Hence, the valence electron present in oxygen is 6 (see below image).

Hence in a SiO2 molecule, 

Valence electrons given by Silicon (Si) atom = 4
Valence electrons given by each Oxygen (O) atom = 6
So, total number of Valence electrons in SiO2 molecule = 4 + 6(2) = 16

Step #2: Select the center atom

While selecting the 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 SiO2 molecule, if we compare the silicon atom (Si) and oxygen atom (O), then the silicon is less electronegative than oxygen.

So, silicon should be placed in the center and the remaining 2 oxygen atoms will surround it.

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

Now in the above sketch of SiO2 molecule, put the two electrons (i.e electron pair) between each silicon atom and oxygen atom to represent a chemical bond between them.

These pairs of electrons present between the Silicon (Si) and Oxygen (O) atoms form a chemical bond, which bonds the silicon and oxygen atoms with each other in a SiO2 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 SiO2, the outer atoms are oxygen atoms.

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

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

Also, all the 16 valence electrons of SiO2 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 SiO2.

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 only 4 electrons. So it does not fulfill the octet rule.

Now, in order to fulfill the octet of silicon atom, we have to move the electron pair from the outer atom (i.e oxygen atom) to form a double bond.

Still, the octet of silicon atom is not fulfilled as it has only 6 electrons.

So again moving the electron pair from another oxygen atom, we will get the following structure.

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

Step #6: Final step – 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 oxygen atom (O).

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 Oxygen:
  Valence electron = 6 (as it is in group 16)
  Nonbonding electrons = 4
  Bonding electrons = 4

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

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

Hence, there will not be any change in the above structure and the above lewis structure of SiO2 is the final stable structure only.

Each electron pair (:) in the lewis dot structure of SiO2 represents the single bond ( | ). So the above lewis dot structure of SiO2 can also be represented as shown below.

Related lewis structures for your practice:
Lewis structure of SiH4
Lewis structure of ClO4-
Lewis structure of ClO-
Lewis structure of NOCl
Lewis structure of SeO2

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