ClO4- Lewis Structure in 5 Steps (With Images)

So you have seen the above image by now, right?

Let me explain the above image in short.

ClO4- (Perchlorate ion) lewis structure has a Chlorine atom (Cl) at the center which is surrounded by four Oxygen atoms (O). There are 3 double bonds and 1 single bond between the Chlorine atom (Cl) and each Oxygen atom (O). There are 2 lone pairs on double bonded Oxygen atoms (O) and 3 lone pairs on single bonded Oxygen atom (O).

If you haven’t understood anything from the above image of ClO4- lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of ClO4^– ion.

So let’s move to the steps of drawing the lewis structure of ClO4^– ion.

Steps of drawing ClO4- lewis structure

Step 1: Find the total valence electrons in ClO4- ion

In order to find the total valence electrons in ClO4- ion (perchlorate ion), first of all you should know the valence electrons present in chlorine atom as well as oxygen atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)

Here, I’ll tell you how you can easily find the valence electrons of chlorine as well as oxygen using a periodic table.

Total valence electrons in ClO4- ion

→ Valence electrons given by chlorine atom:

Chlorine is group 17 element on the periodic table. ^[1] Hence the valence electrons present in chlorine is 7.

You can see the 7 valence electrons present in the chlorine atom as shown in the above image.

→ Valence electrons given by oxygen atom:

Oxygen is group 16 element on the periodic table. ^[2] Hence the valence electrons present in oxygen is 6.

You can see the 6 valence electrons present in the oxygen atom as shown in the above image.

Hence, 

Total valence electrons in ClO4- ion = valence electrons given by 1 chlorine atom + valence electrons given by 4 oxygen atoms + 1 more electron is added due to one negative charge = 7 + 6(4) + 1 = 32.

Step 2: Select the central atom

For selecting the center atom, you have to remember that the atom which is less electronegative remains at the center.

Now here the given ion is ClO4- ion and it contains chlorine atom (Cl) and oxygen atoms (O).

You can see the electronegativity values of chlorine atom (Cl) and oxygen atom (O) in the above periodic table.

If we compare the electronegativity values of chlorine (Cl) and oxygen (O) then the chlorine atom is less electronegative.

So here the chlorine atom (Cl) is the center atom and the oxygen atoms (O) are the outside atoms.

Step 3: Connect each atoms by putting an electron pair between them

Now in the ClO4 molecule, you have to put the electron pairs between the chlorine atom (Cl) and oxygen atoms (O).

This indicates that the chlorine (Cl) and oxygen (O) are chemically bonded with each other in a ClO4 molecule.

Step 4: Make the outer atoms stable

Now in this step, you have to check the stability of the outer atoms.

Here in the sketch of ClO4 molecule, you can see that the outer atoms are oxygen atoms.

These outer oxygen atoms are forming an octet and hence they are stable. 

Also, in step 1 we have calculated the total number of valence electrons present in the ClO4- ion.

The ClO4- ion has a total 32 valence electrons and all these valence electrons are used in the above sketch.

Hence there are no remaining electron pairs to be kept on the central atom. 

So now let’s proceed to the next step.

Step 5: Check the stability of lewis structure

Now you have come to the final step in which you have to check the stability of lewis structure of ClO4- ion.

The stability of lewis structure can be checked by using a concept of formal charge.

In short, now you have to find the formal charge on chlorine (Cl) atom as well as oxygen (O) atoms present in the ClO4 molecule.

For calculating the formal charge, you have to use the following formula;

Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons

You can see the number of bonding electrons and nonbonding electrons for each atom of ClO4 molecule in the image given below.

For Chlorine (Cl) atom:
Valence electrons = 7 (because chlorine is in group 17)
Bonding electrons = 8
Nonbonding electrons = 0

For Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 2
Nonbonding electrons = 6

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
Cl	=	7	–	8/2	–	0	=	+1
O	=	6	–	2/2	–	6	=	-1

From the above calculations of formal charge, you can see that the chlorine (Cl) atom has +1 charge while the oxygen atoms has -1 charges.

So let’s keep these charges on the respective atoms of the ClO4 molecule.

The above image shows that the lewis structure of ClO4 is not stable.

So we have to minimize these charges by shifting the electron pairs from the oxygen atoms to the chlorine atom.

After shifting the electron pairs from the oxygen atom to the chlorine atom, the charges on central chlorine atom as well as three oxygen atoms becomes zero. And this is a more stable lewis structure. (see below image).

There is one -ve charge left on the oxygen atom, which gives -1 formal charge on the ClO4 molecule.

This overall -1 charge on the ClO4 molecule is represented in the image given below.

In the above lewis dot structure of ClO4- ion, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of ClO4- ion.

I hope you have completely understood all the above steps.

For more practice and better understanding, you can try other lewis structures listed below.

Try (or at least See) these lewis structures for better understanding:

ClO- lewis structure	NOCl lewis structure
SeO2 lewis structure	OCl2 lewis structure
CH3COOH (acetic acid) lewis structure	SiCl4 lewis structure