Simple Method for writing Lewis Structures of perchloric acid HClO4
A simple procedure for writing Lewis 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 perchloric acid HClO4. Perchloric acid is a colorless liquid. It is a stronger acid than nitric and sulfuric acid. Perchloric acid is useful for preparing ammonium perchlorate, an important rocket fuel component. It is also used as:
- a solvent for metals and alloy
- a dehydrating agent, particularly in the determination of silica in iron and steel and in cement and other silicate materials
- an oxidizing agent, especially in the determination of chromium in steel, ferrochrome, chromite, leather
- a solvent for sulfide ores for the determination of copper and other metals
How can we construct the Lewis structure of HClO4 ?
Step 1: Connect the atoms with single bonds. Chlorine is the central atom:
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 5 since HClO4 consists of 6 atoms but one of them is a hydro gen atom (remember n is the number of atoms in a molecule minus the hydrogen atoms).
Where V = (1 + 7 + 4*6 ) = 32
Therefore, P = 6n + 2 – V = 6 * 5 + 2 – 32 = 0
So there are no π electrons in HClO4 and therefore the structure of Step 1 is the Lewis structure.
Electrons are placed around each atom so that the octet rule is obeyed. Formal charges are assigned and equalized using resonance.
Step 3 & 4: The Lewis structure for HClO4 is as follows:
