Simple Method for writing Lewis Structures for N2O2- Example #21

A simple procedure for writing Lewis structures is given in a previous article entitled “Lewis Structures and the Octet Rule”. Relevant worked examples were given in the following articles: Examples #1, #2, #3 , #4, #5, #6,  #7,  #8, #9, #10, #11, #12, #13, #14,  #15, #16, #17, #18, #19 and #20.

Another example  for writing Lewis structures following the above procedure is given bellow:

Let us consider the case of dinitrogen dioxide (N₂O₂). Dinitrogen dioxide is the brown film we see in the atmosphere all over highly polluted cities.

 Step 1: Connect the atoms with single bonds. The central atoms are the nitrogen atoms.

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

Where n in this case is 4 since N₂O₂ consists of four atoms.

Where V = (5 + 5 + 6 + 6 ) = 22  

Therefore, P = 6n + 2 – V = 6 * 4 + 2 – 22 = 4   So there are 4π electrons in N₂O₂ and that means 2 double bonds or a triple bond must be added to the structure in Step 1.

 

Step 3 & 4: The Lewis structure for N₂O₂  is as follows:

Figure 1: Lewis structures for N₂O₂. Structure #1 is the only experimentally observed structure. Structure #4 is the least plausible since O the most electronegative of the elements in the above structure has a + charge and N the least electronegative of the atoms present a – charge.