A review of ClO4’s atomic and molecular structure as well as its polarity

There are many salts that include perchlorate ion, or [ClO4]-. You may be surprised to learn that ClO4 may be found on the red planet as well.

It has a wide range of applications, ranging from food packaging to rocket propellants as oxidizers.

Exposure to water and food, however, can be hazardous to human health and have serious adverse effects.

Salts of perchlorate ion with sodium, ammonium, or potassium often have a molar mass of 99.45 g/mol or higher. Most commonly, it takes the form of a white solid, but it can also react with acids to create acid ( perchloric acid).

Let’s take a closer look at ClO4’s chemical bonds in more detail.

ClO4’s Lewis structure

One of chemistry’s most essential and fascinating topics is chemical bonding.

We need to see how atoms in a molecule establish covalent connections with one another if we are to understand the underlying science.

We can use the Lewis Structure or electron-dot structure to sketch a line diagram of atoms and electrons in a compound, as well as the electrons and bonds that connect them.

A Lewis structure diagram is a visual representation of a chemical compound’s molecular arrangement.

The first step in the process

The molecule’s valence electron count is tallied as the first stage in the aforementioned procedure.

The number of electrons an atom has in its outermost shell is referred to as its valence electrons.

In order to figure out the Lewis Structure, we must need two symbols: ‘+’ and ‘-.’

“+” when there is a decrease in electrons and “-” when there is an increase in electrons

The second step

To summarise, we’ve worked out how many electrons each atom has, and we’re done here. As the next phase, we’ll figure out which atom will serve as the nucleus.

If we have a firm grasp of the electronegativity notion, locating the nucleus will be a breeze. The centre atom is the one with the most binding sites.

This is the third step.

Doesn’t it make our job a lot easier to identify the central atom?

Until far, we have only had to draw the atoms and their valence states as well as any single bonds that may have been formed between the atoms.

The fourth and last step

Atoms are encouraged to seek for the nearest possible noble gas combinations by the octet rule. Assuming that just two electrons are required in hydrogen’s outermost shell to achieve helium configuration, all other atoms tend to have eight valencies.

Octet setup is the technical term for this. To begin, we’ll start with atoms that have the most electropositive outer shells and work our way out to the least electropositive.

This is the final step.

We’ll move on to multiple bond formation in the penultimate stage now that we’ve discovered the octet configurations.

The Lewis Structure diagram can demonstrate whatever inclination an atom has to create double or triple bonds by using double or triple straight lines.


Isn’t it possible to have many Lewis Structure diagrams for a single molecule? This can be a bit tricky.

We must rely on the formal charge to generate a unique LS for each molecule. As a result, you’ll be hit with

provides an ideal Lewis structure by distributing bonding electrons among the bonded atoms in an equal proportion

As a result, the only thing left to accomplish in this final phase is to figure out the official charge.

We can quickly and simply determine the formal charge using the formula shown in the diagram above.

For the time being, let’s concentrate on ClO4.

At the very beginning, calculate the valency:

Because it is a halogen, chlorine falls under the purview of halogen family number 7, which includes the other halogens. There are seven valence electrons in this atom.

Unlike the other three elements, oxygen has six electrons in its valence shell due to its membership in the chalcogen family of group 6.

ClO4 has a total of 31 valence electrons, which are calculated as follows: 71 + 64

Although ClO4 is an ion that is negatively charged, we already know that it is an ion.

So, the total number of electrons is 32.

Because chlorine is the smallest atom in this system, it will be called the “core” atom.

The skeleton diagram is now complete, so let’s get started.

The dot structure appears to have been completed after creating the skeletal sketch and making the valence electrons 32 with 8 around each. However, there is one notable exception.

This isn’t finished yet. We’ll need to verify the formal charge.

There are three formal charges in the formula above, and each oxygen has one formal charge, therefore we know that chlorine is charged with +3.

To put it another way, the total formal charge is -1.

We shall establish three double bonds around Chlorine, each one containing an Oxygen atom, in order to bring the formal charge close to zero.

By doing so, three of the oxygen atoms are now doubly linked to chlorine, while only one is. The single-bonded oxygen is responsible for the negative charge on [ClO4]-1.

Our diagrammatic portrayal of perchlorate ions in the Lewis Structure has been completed.

Geometry of the ClO4 Molecular Formula

Understanding the molecule’s two-dimensional structure doesn’t provide you the whole picture of its properties and nature.

There are advantages and disadvantages to using Lewis Structure as a framework for understanding bonds and formal charge notions.

In order to gain a better understanding of a specific molecule, we must also understand its 3-dimensional structure.

The form of a molecule can be determined using a technique known as molecular geometry.

Now, how do you work out the ion’s molecular structure?

There is, of course, the VSEPR model, which stands for Valence Shell Electron Pair Repulsion Theory. New terms like steric number and electron repulsion are introduced as part of this development of the LS notion (minimum repulsion between valence electron pairs is supported by chemical nature).

In the case of [ClO4]-, we’ve previously discovered that chlorine is the core element. A closer study of the lewis structure reveals that all of the chlorine-oxygen links have either single or double electrons attached to them ( in this case 1 single and 3 double bonds).

As a result, there are no Chlorine solitary pairs present.

If you’re not familiar with the phrase, a steric number is essentially a coordination number, which is why central Cl has a value of 4.

According to the VSEPR model, the perchlorate ion’s molecular structure is tetrahedral, with each bond having an angle of 109 degrees.

Hybridization of ClO4

So, what exactly is a hybrid?

One of the most important theories in chemical bonding is hybridization. Lewis structure and molecular geometry are merely the first steps towards learning about hybridization if we already know them.

Numerous peculiarities distinguish elements and compounds from one another. That one element can exhibit distinct properties when reacting with another element or even the same one is something you’re aware of?

Hybridization, on the other hand, plays a critical function here.

Hybridized orbitals are formed when the atomic orbitals combine and take on new energies and properties.

The atomic number of chlorine is 17. In terms of its electronic configuration, it is [Ne]3s23p5.

Oxygen atoms form a sigma bond with the centre chlorine atom. There are three sigma and pi double bonds in this molecule.

A simple formula can be used to calculate hybridization:


In this case, H is the hybridization value.

Valence electrons are referred to as “V” in abbreviation.

M stands for a single-valent atom.

Caution: C is the cation


When V=7, we have a problem ( according to central chlorine)



In addition, C is equal to zero.

H is now equal to 0.5(7+1) which equals 4.

As a result, ClO4 hybridization is sp3.

Consider the hybrid orbitals associated to lone electron pairs and sigma bonds when you compute hybridization. This is important to remember. The pi bonds are irrelevant to us.

Polarity of ClO4

When discussing a molecule’s chemical bonding, words like polarity and dipole moment are crucial.

The type of a molecule’s chemical bonds affects whether or not it is polar or non-polar. Due to the difference in electronegativity between the atoms, this results in a spread of positive and negative charges.

Dipole moment — net dipole moment when 0, a molecule is referred to as non-polar. This can be quantified.

D is the product of Q and R

Dipole moment (D), charge on atoms (Q), and distance between atoms (R) are all denoted by the letters D, Q, and R respectively.

Perchlorate ions are non-polar, in case you didn’t know.

Due to the anionic charge, this may come as a surprise. Despite the fact that ClO2- is very polar, ClO4- is not.

Since the ClO4 ion is nonpolar, it can’t be used in polarising solutions.

The Cl and O bonds are polar because oxygen has a greater electronegativity value than chlorine. The net dipole moment of perchlorate is 0 because of the equal strength of the four internal bonds that give birth to the four resonance tetrahedral structures.


Perchlorate’s ion, [ClO4]-, has been described in length in this article using the Lewis structure, Molecular Geometry, Hybridization, and Polarity.

This has been a lengthy discussion, and we hope that you now understand the anion’s bonding nature and intrinsic features.

Continuing education is the best way to keep up with the times

Read more: Hybridization and Lewis Structures for the BF3 Molecule

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.


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