Lewis structure of CBr4

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The Lewis structure of CBr₄ contains four single bonds, with carbon in the center, and four bromines on either side. There are three lone pairs on each bromine atom, and the carbon atom does not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of CBr₄:

#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)

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… carbon is a group 14 element and bromine is a group 17 element. Hence, carbon has four valence electrons and bromine has seven valence electrons.

Now CBr₄ has one carbon atom and four bromine atoms.

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

Therefore, the total number of valence electrons = 4 + 28 = 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 carbon and bromine as follows:

Electronegativity value of carbon = 2.55
Electronegativity value of bromine = 2.96

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

So now, put carbon in the center and bromines on either side. And draw the rough skeleton structure for the Lewis structure of CBr₄ something like this:

Also read: How to draw Lewis structure of SeO₂ (6 steps)

#2 Show chemical bond

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

Also read: How to draw Lewis structure of ICl₄^– (4 steps)

#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 carbon is a period 2 element, so it can not keep more than 8 electrons in its last shell. And bromine is a period 4 element, so it can 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 bromines, so each bromine will get three lone pairs. And the central atom (carbon) will not get any lone pair, because all twelve lone pairs are used.

So the Lewis structure of CBr₄ looks something like this:

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

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

Also read: How to draw Lewis structure of SiCl₄ (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 carbon atom

Valence electrons = 4
Nonbonding electrons = 0
Bonding electrons = 8

Formal charge = 4 – 0 – ½ (8) = 0

• For each bromine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of CBr₄ looks something like this:

In the above structure, you can see that the formal charges of both (carbon and bromine) are zero. Therefore, this is the stable Lewis structure of CBr₄.

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

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Related

• Lewis structure of SeO₂
• Lewis structure of ICl₄^–
• Lewis structure of SiCl₄
• Lewis structure of SiF₄
• Lewis structure of OCN^–

External video

• CBr4 Lewis Structure: How to Draw the Lewis Structure for CBr4 – YouTube • Wayne Breslyn

External links

• Drawing the Lewis Structure for CBr4 (Carbon Tetrachloride) – The Geoexchange
• CBr4 Lewis Structure in 6 Steps (With Images) – Pediabay
• CBr4 lewis structure, molecular geometry, polar or nonpolar, bond angle? – Topblogtenz
• Draw the Lewis structure for CBr4 – Homework.Study.com
• CBR4 Lewis Structure, Geometry – Kemicalinfo
• draw the lewis structure for carbon tetrabromide, cbr4 – Brainly
• CBr4 Electron dot structure | Chemistry, Science – ShowMe
• Lecture 15: Lewis Structures – Carbon Tetrabromide – Cbr4 – iLectureOnline
• What is the molecular geometry shape of CBr4? – Quora
• Draw the Lewis structure for carbon tetrabromide – Chegg
• How to draw a CBr4 Lewis Structure? – Science Education and Tutorials
• Draw the Lewis structure of CBr4 and then determine its electron domain and molecular geometries – Numerade
• What is the Lewis dot structure for CBr4? – Answers
• Draw the Lewis dot structure for CBr4 – Bartleby