Simple Method for writing Lewis Structures for N2O3 - #23

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, #20, #21 and #22.

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

Let us consider the case of dinitrogen trioxide (N₂O₃).
 

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 5 since N₂O₃ consists of five atoms.

Where V = (5 + 5 + 6 + 6 + 6 ) = 28  

Therefore, P = 6n + 2 – V = 6 *5 + 2 – 28 = 4  Therefore, there are 4π electrons in N₂O₃ and 2 double bonds or a triple bond must be added to the structure in Step 1.

Step 3 & 4: The Lewis structure for N₂O₃  is as follows:

Figure 1: Lewis structure for N₂O₃

Another resonance structure of the above is given below but is less plausible compared to the one given in Figure 1 due to large charge separation and the adjacent positive charges.

Figure 2: A less plausible Lewis resonance structure of N₂O₃ due to large charge separation comparing to the structure in Figure 1