Lewis structure of BrO4-

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The Lewis structure of BrO₄^– contains three double bonds and one single bond, with bromine in the center, and four oxygens on either side. The top oxygen atom, left oxygen atom, and right oxygen atom has two lone pairs. The bottom oxygen atom has three lone pairs, and the bromine atom does not have any lone pair.

Plus, there is a negative (-1) charge on the bottom oxygen atom.

Steps

By using the following steps, you can easily draw the Lewis structure of BrO₄^–.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)
#5 Convert lone pair and calculate formal charge again (if formal charges are not closer to zero)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… bromine is a group 17 element and oxygen is a group 16 element. Hence, bromine has seven valence electrons and oxygen has six valence electrons.

Now BrO₄^– has one bromine atom and four oxygen atoms.

So the total number of valence electrons = valence electrons of bromine atom + (valence electrons of oxygen atom × 4)

And BrO₄^– has a negative (-1) charge, so we have to add one more electron.

Therefore, the total number of valence electrons = 7 + 24 + 1 = 32

• Now decide the central atom

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for bromine and oxygen as follows:

Electronegativity value of bromine = 2.96
Electronegativity value of oxygen = 3.44

Obviously, bromine is less electronegative than oxygen. Hence, assume that bromine is the central atom.

So now, put bromine in the center and oxygens on either side. And draw the rough skeleton structure for the Lewis structure of BrO₄^– something like this:

Also read: How to draw Lewis structure of HOCN (5 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since bromine is surrounded by four oxygens, use eight electrons to show four chemical bonds as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 32 valence electrons. And in the above structure, we have already used eight valence electrons. Hence, twenty-four valence electrons are remaining.

Two valence electrons represent one lone pair. So twenty-four valence electrons = twelve lone pairs.

Note that bromine is period 4 element, so it can keep more than 8 electrons in its last shell. And oxygen is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are oxygens, so each oxygen will get three lone pairs. And the central atom (bromine) will not get any lone pair, because all twelve lone pairs are used.

So the Lewis structure of BrO₄^– looks something like this:

In the above structure, you can see that the octet is completed on the central atom (bromine), and also on the outside atoms. Therefore, the octet rule is satisfied.

Now calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of SF₅^– (4 steps)

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

• For bromine atom

Valence electrons = 7
Nonbonding electrons = 0
Bonding electrons = 8

Formal charge = 7 – 0 – ½ (8) = +3

• For each oxygen atom

Valence electrons = 6
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 6 – 6 – ½ (2) = -1

Mention the formal charges of atoms on the structure. So the Lewis structure of BrO₄^– looks something like this:

In the above structure, you can see that the formal charges of atoms are not closer to zero. Therefore, convert lone pair and calculate formal charge again.

Also read: How to draw Lewis structure of SeF₂ (4 steps)

#5 Convert lone pair and calculate formal charge again

As mentioned earlier, bromine is a period 4 element, so it can keep more than 8 electrons in its last shell.

So convert one lone pair from the three oxygen atoms to make a new bond with the bromine atom. And then, the Lewis structure of BrO₄^– looks something like this:

Now one last thing we need to do is, calculate the formal charge again and check the stability of the above structure.

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

• For bromine atom

Valence electrons = 7
Nonbonding electrons = 0
Bonding electrons = 14

Formal charge = 7 – 0 – ½ (14) = 0

• For top oxygen, left oxygen, and right oxygen atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 0

• For bottom oxygen atom

Valence electrons = 6
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 6 – 6 – ½ (2) = -1

Mention the formal charges of atoms on the structure. So the Lewis structure of BrO₄^– looks something like this:

In the above structure, you can see that the formal charges of atoms are closer to zero. Therefore, this is the most stable Lewis structure of BrO₄^–.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

Now BrO₄^– is an ion having a negative (-1) charge, so draw brackets around the above Lewis structure and mention that charge on the top right corner. And then, the Lewis structure of BrO₄^– looks something like this:

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Related

• Lewis structure of HOCN
• Lewis structure of SF₅^–
• Lewis structure of SeF₂
• Lewis structure of NO₄^3-
• SF₃⁺ Lewis structure

External video

• How to Draw the Lewis Dot Structure for BrO4- (See note in description!) – Wayne Breslyn

External links

• BrO4- Lewis Structure in 5 Steps (With Images) – Pediabay
• Draw the best lewis structure for bro4- and determine the formal charge on bromine – Brainly
• What is BrO4- Lewis structure? – Homework.Study.com
• Draw the best Lewis structure for Bro4 and determine the formal charge on bromine – Chegg
• What is the BrO4 Lewis structure? – Quora
• How many equivalent resonance structures are possible for the perbromate ion (BrO4-)? – Studocu
• Draw a Lewis Structure for BrO4- in which the central atom has a formal charge of zero – Bartleby
• Draw the Lewis structure for BrO4. What is the hybridization on the Br atom? – Numerade
• What is the correct name for the BrO4 -1 ion? – Answers