How to draw Lewis dot structures | POCl3 Phosphorous oxychloride | Chemistry Net

How to draw Lewis dot structures | POCl3 Phosphorous oxychloride

A simple procedure for writing Lewis dot structures was given in a previous post entitled “Lewis Structures and the Octet Rule”.
Several worked examples relevant to this procedure were given in previous posts please see the Sitemap - Table of Contents (Lewis Electron Dot Structures).

Let us examine the case of phosphorous oxychloride POCl3. How can we construct the POCl3 resonance Lewis dot structure?

Step 1: Connect the atoms with single bonds. The less electronegative is the phosphorous atom. Hence, the P atom is going to be the central atom. Recall that electronegativity decreases as we move away from the fluorine atom in the periodic chart.

Simple method for drawing Lewis dot structures

Fig.1: Connect the atoms of the POCl3 molecule with single bonds

 Step 2:  Calculate the # of electrons in π bonds (multiple bonds) using  formula (1)

Where n in this case is 5. Where V = (7 +5 + 7 + 6 + 7 )  = 32 , V is the number of valence electrons of the POCl3.molecule.
Therefore, P = 6n + 2 – V = 6 * 5 + 2 – 32  = 0     So, there is no double bond.

Step 3 & 4: The resonance Lewis electron dot structures  of POCl3 are as follows:

Lewis electron dot structures simple method
Fig. 2 : Electron dot structures of POCl3

 Please, watch the following video on how to draw Lewis structures:


  1. I think Figure 2 has two more electrons than it should. Remove a lone pair on the oxygen.

    1. Thank you David! It is a typo. Oxygen is allowed to have a max. of 8 electrons! A lone pair must be removed

  2. In the case of POCl3, the Lewis structure offers not only a window into its atomic arrangement but also into its functional capacities in diverse scientific arenas.