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:
WoOoOoOoW
ReplyDeleteThe easiest way ever, GREETINGS :)
what is the functional group in perchloric acid functional group perchloric acid
ReplyDeleteChlorine cannot have 14 electrons around it though so wouldn't you have to stop at 2 double bonds and just keep the least number of formal charges?
ReplyDeleteAmanda, chlorine is a third row element. It is allowed to have an expanded octet. The outer shell configuration is 3s23p5 (a total of 7 valence electrons). Chlorine can have 14 electrons around it but it can "own" only 7. Structure #3 above is correct since according to the bonding chlorine "owns" 7 electrons. Structures #2 and #1 are contributors to the resonance. Structure #2 is more probable than #1 due to less charge separation.
DeleteCheck also the following reference "Chemical Structure and Bonding" by H.B. Gray (link: https://books.google.com/books?id=q77rPHP5fWMC&lpg=PA102&ots=qShDkRpKcu&dq=perchloric%20acid%20lewis%20structure&pg=PA103#v=onepage&q=perchloric%20acid%20lewis%20structure&f=false). Thank you for asking!
Could you please explain ( the amount of equivalent resonance structure that is needed to describe the Lewis structure of HClO4 equals: 1 or 2 or 3 or 4 )
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