Dot Structure of chromium trioxide CrO3

Lewis Electron Dot Structure of

Chromium Trioxide CrO₃

A simple procedure for writing Lewis electron 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).

Another example  for writing Lewis structures following the above procedure is given below.

Let us consider the case of the Lewis electron dot structures of chromium trioxide CrO₃. Chromium is an essential nutrient required for normal sugar and fat metabolism and works primarily by potentiating the action of insulin. It is included in several dietary supplements and vitamins. The chemical formula is CrO₃ .

How can we draw the Lewis electron dot structures of chromium trioxide CrO₃?

 

Step 1: Connect the atoms with single bonds.

 

Step 2: Calculate the # of electrons in π bonds (multiple bonds) using  formula (1) in the article entitled “Lewis Structures and the Octet Rule”. 

Where n in this case is 4. Where V = (6 + 6 + 6 + 6 ) = 24 , V is the number of valence electrons of the molecule. Therefore, P = 6n + 2 – V = 6 * 4 + 2 – 24 = 2

So, there is one double bond in the molecule.

Step 3 & 4: The Lewis resonance structures of chromium trioxide CrO₃ are as follows: