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 and #11.

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

Let us consider the case of azide ion (N

_{3}^{-}). Azides are energy-rich molecules with many applications. Sodium azide (NaN_{3}), for example, is used as a preservative, mutagen, biocide and assay reagent. It has also been used as a component in the gas generators used to inflate certain automotive airbag safety systems, providing the source of nitrogen gas necessary to inflate the bag instantaneously. Organic azides are capable of a great diversity of organic reactions and are important components in Click Chemistry.__Step 1__: Connect the atoms with single bondsFig. 1: Connecting the N atoms of the azide ion with single bonds according to step 1 of the method |

__Step 2__: Calculate the # of electrons in π bonds (pi bonds, multiple bonds) using formula**(1)**in the article entitled “Lewis Structures and the Octet Rule”.:
Where n in this case is 3 since N

_{3}^{-}consists of three atoms.
Where V = (5 + 5 + 5) – (-1) = 16

Therefore, P = 6n + 2 – V = 6 * 3 + 2 – 16 = 4

**Therefore, there are 4****π electrons (pi electrons) in**N_{3}^{-}_{}

**and that means that 2 double bonds or 1 triple bond must be added to the structure of Step 1.**__Step 3 & 4__: The Lewis structures for^{ }N_{3}^{- }are as follows:Figure 2: Lewis structures for N_{3}^{-} _{.} Structure 1 is the most plausible since it has the smallest charge separation . |

Thank you! Was very useful. Helped alot! ��

ReplyDeleteThanks. It was very helpful

ReplyDeletedidn't understand step 2. How can I say that N3- will have 2 double bonds or a triple bond?

ReplyDelete