Lewis Structures of peroxy nitric acid HO2NO2

A simple method for writing Lewis Dot Structures is given in a previous article 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 consider the case of peroxy nitric acid HO₂NO₂ :

                                  

Step 1: Connect the atoms with single bonds.

The central atom will be the N atom since it is the less electronegative (H is a terminal atom – it cannot be a central atom).  Connect the atoms with single bonds.

Fig. 1 : Connect the atoms of peroxy nitric acid with single bonds.

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

Where n in this case is 5 since  HO₂NO₂  consists of six atoms but one of them is a H atom.

Where V = (1 + 6 + 6 + 5 + 6 + 6) = 30  

Therefore, P = 6n + 2 – V = 6 * 5 + 2 – 30 = 2      Therefore  there are 2 π electrons in HO₂NO₂ and so 1 double bond must be added to the structure of Step 1.

Step 3 & 4: One double bond must therefore be placed through the 3 N-O bonds. Therefore, the Lewis structures for HO₂NO₂ are as follows:

 

Figure 2: Lewis structures of peroxy nitric acid