Lewis Structure of P2O5 (With 5 Simple Steps to Draw!)

I’m super excited to teach you the lewis structure of P2O5 in just 5 simple steps.

Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of P2O5 molecule.

So, if you are ready to go with these 5 simple steps, then let’s dive right into it!

Lewis structure of P2O5 contains two Phosphorus (P) atoms at the center and it is surrounded by five Oxygen (O) atoms. The two Oxygen are double bonded while the other three Oxygen are single bonded with Phosphorus. One of the Oxygen atoms forms a bond with both the Phosphorus atoms. 

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 P2O5).

5 Steps to Draw the Lewis Structure of P2O5

Step #1: Calculate the total number of valence electrons

Here, the given molecule is P2O5. In order to draw the lewis structure of P2O5, first of all you have to find the total number of valence electrons present in the P2O5 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 P2O5

• For Phosphorus: 

Phosphorus is a group 15 element on the periodic table. ^[1]

Hence, the valence electrons present in phosphorus is 5 (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 P2O5 molecule,

Valence electrons given by Phosphorus (P) atom = 5
Valence electrons given by each Oxygen (O) atom = 6
So, total number of Valence electrons in P2O5 molecule = 5(2) + 6(5) = 40

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 P2O5 molecule, if we compare the phosphorus atom (P) and oxygen atom (O), then the phosphorus is less electronegative than oxygen.

So, phosphorus atoms should be placed in the center and the remaining 5 oxygen atoms will surround it.

(Note: This is a little bit tricky. Here in the sketch, it looks like the oxygen is a center atom. But it is not. The oxygen which is at the center is considered as an outer atom. This is because the oxygen is more electronegative than phosphorus, and the more electronegative atom should be considered as an outer atom. And so, here the 2 phosphorus atoms are the central atoms. By doing this you will get the more stable lewis structure.)

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

Now in the above sketch of P2O5 molecule, put the two electrons (i.e electron pair) between each phosphorus atom and oxygen atom to represent a chemical bond between them.

These pairs of electrons present between the Phosphorus (P) and Oxygen (O) atoms form a chemical bond, which bonds the phosphorus and oxygen atoms with each other in a P2O5 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 P2O5, 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 40 valence electrons of P2O5 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.

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 atoms (i.e phosphorus) has an octet or not. 

In simple words, we have to check whether both the central Phosphorus (P) atoms have 8 electrons or not.

As you can see from the above image, both the phosphorus atoms have only 6 electrons. So they do not fulfill the octet rule.

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

Now you can see from the above image that the central atoms (i.e phosphorus), are having 8 electrons. 

This indicates that both these phosphorus atoms are now stable, and this is the stable lewis structure of P2O5.

Each electron pair (:) in the lewis dot structure of P2O5 represents the single bond ( | ). So the above lewis dot structure of P2O5 can also be represented as shown below.

Related lewis structures for your practice:
Lewis Structure of C2Br4
Lewis Structure of TeBr2
Lewis Structure of AsF5
Lewis Structure of HI
Lewis Structure of PO3- 

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