Carbon tetrachloride is a colorless liquid with a sweet smell and its chemical formula is CCl4. It is highly dangerous for our central nervous system if contacted with a high concentration including vapors.
In this article, we will discuss Carbon tetrachloride (CCl4) lewis dot structure, molecular geometry, polar or non-polar, Bond angle, hybridization, etc.
Important properties of Carbon tetrachloride
It is non-flammable and doesn’t dissolve in water quickly.
It has a sweet smell and odor like Chloroform.
It is non-combustible.
CCl4 has a boiling point of 76.72 °C and a melting point of −22.92 °C.
It has a Tetragonal coordination geometry.
Uses of Carbon tetrachloride
It is used as a solvent for halogenation and as an agricultural fumigant.
It is used as a fire extinguisher.
For the detection of neutrinos.
In the manufacturing of various chemicals.
It is used in stamp collecting and to reveal watermarks on postage stamps.
How to draw Carbon tetrachloride (CCl4) lewis structure?
CCl4 lewis’s structure is made up of one carbon atom that is situated at the middle position and four chlorine atoms that are at the surrounding position. The total lone pair present in the CCl4 lewis dot structure is 12.
Lone pairs of electrons do not involve in chemical bonds and it is represented as a dot in the lewis diagram.
To draw the stable Carbon tetrachloride lewis structure, we have to represent the valence electron of each atom within a molecule.
Steps for drawing the stable lewis dot structure of CCl4
1. Count total valence electron in CCl4
In the first step of every lewis diagram, we need to know how many valence electrons are present in a molecule. For finding the valence electron in CCl4, we have to know the periodic group number of Carbon and chlorine.
The periodic group of carbon is 14 and for chlorine, it is 17. Hence carbon has 4 valence electrons present in its outermost shell and chlorine has 7 valence electrons present in its outermost shell.
⇒ Valence electron of carbon = 4 [∴Periodic group of carbon = 14]
⇒ Valence electron of chlorine = 7 [∴Periodic group of chlorine = 17]
∴ Total valence electron available for drawing the lewis structure of CCl4 = 4 + 7*4 = 32 electrons.
2. Find the least electronegative atom and placed it at center
In this step, We will find the central atom to place in the lewis diagram by determining the least electronegative atom in between Carbon or Chlorine.
As electronegativity increase from left to right in the periodic table. Hence carbon is a less electronegative atom than chlorine. Therefore carbon is placed at the center and chlorine spaced evenly around it.
3. Connect carbon and chlorine with a single bond
Now we are going to start drawing the CCl4 lewis structure by connecting chlorine to carbon with the help of a single bond.
Now look at the above structure and find how many valence electrons we used till now. Valence electron means electrons that are shareable or transferable.
Hence, 4 single bonds are used in the above structure to connect chlorine with carbon and 1 single bond contains 2 electrons.
Therefore, 4 single bonds mean 8 electrons are used in the above structure from a total of 32 valence electrons.
∴ (32 – 8) = 24 valence electrons
So, we are left with 24 valence electrons more.
4. Placed remaining valence electrons starting from outer atom first
After the third step, we have a total of 24 valence electrons left and we need to put these valence electrons to the outer atom(chlorine) first for completing its octet.
Chlorine needs 8 electrons in its valence shell to complete its octet. So, put these remaining valence electrons around each chlorine atom.
Look at the above structure, we put 6 valence electrons around each chlorine atom to complete their octets because chlorine already shares 2 electrons with the help of a single bond so, it only needs 6 more electrons to complete their octet.
5. Complete central atom octet and make covalent bond if necessary
Carbon is the central atom and it needs 8 electrons in the valence shell to complete its octet. But Carbon already shares 8 electrons with the help of 4 single bonds connected with a chlorine atom.
Lewis dot structure for CCl4
As you see in the above lewis dot structure of CCl4, each atom(chlorine and carbon) completes their octet comfortably, and no need to make any covalent bond because we got our stable Carbon tetrachloride lewis structure.
What are the molecular geometry of CCl4 and its Bond angle?
The molecular geometry of CCl4 is Tetrahedral and its electron geometry is also tetrahedral with a bond angle of 109.5º. As carbon with four bonded pairs and Sp³ hybridization in a central position and chlorine spread evenly around it all sides.
There are four regions of electron density around the carbon central atom and “The VSEPR theory states that the electron regions around an atom spread out to make each region is as far from the others as possible.”
So, these electron pairs in CCl4 tend to go far from each other and stabilized where the repulsion remains minimum between them.
These electron pairs point towards the corner of the tetrahedron with respect to the minimization of electron pair-electron pair repulsion.
Hence, the final molecular geometry of CCl4 appears like a regular tetrahedron with a bond angle ∠Cl−C−Cl=109.5°.
In most of the cases, central atom with four region of density adopt a tetrahedral structure because repulsion is minimum in electron pairs at this position.
Molecular geometry is the three-dimensional arrangement of atoms in a molecule.
Let’s see how to find CCl4 molecular geometry and its bond angle.
Follow three steps to find CCl4 molecular geometry
1. Find the Number of lone pairs present on the central atom of the CCl4 lewis structure
As per the CCl4 lewis structure, carbon is the central atom that has no lone pair present on it because carbon completes its octet with the help of 4 single bonds.
Or you can determine the lone pair in CCl4 by using the simple formula.
∴ L.P = (V.E. – N.A.)/2
where L.P. = Lone pair on the central atom
⇒ V.E. = valence electron of that central atom
⇒ N.A. = Number of atoms attached to that central atom
So, the valence electron of Carbon is 4, and the number of the attached atom to Carbon is also 4.
Put these values in the given formula-
∴ (4 – 4)/2
= 0 is the lone pair present on the central atom(carbon).
2. Find hybridization number of CCl4
For finding the hybridization number of CCl4, Use the given below formula.
∴ H = N.A. + L.P.
where H = hybridization number
⇒ N.A. = Number of atoms attached to the central atom
⇒ L.P. = lone pairs on that central atom
According to the CCl4 lewis structure, Carbon is the central atom, and the number of the attached atoms to carbon is 4 with the zero lone pair on It.
∴ H = 4 + 0
= 4 is the hybridization number of CCl4
Hence Sp³ is the hybridization of CCl4.
3. Use VSEPR theory or AXN method to determine CCl4 molecular shape/geometry
According to the VSEPR (Valence shell electrons repulsion) theory, if any molecule has 0 lone pair and Sp³ hybridization then the molecular and electron geometry of that molecule is tetrahedral.
Hence molecular geometry of CCl4 is tetrahedral.
CCl4 molecular geometry or shape
Another method we have is AXN for determining the molecular geometry of CCl4.
Let’s see how to use this method.
A represents the central atom.
X represents the bonded pairs of electrons to the central atom.
N represents the lone pairs of electrons on the central atom
As per the CCl4 lewis dot structure, carbon is the central atom that has 4 bonded pairs of electrons and 0 lone pairs on it.
Hence formula of CCl4 becomes AX4.
According to the VSEPR chart, if any molecule represents the AX4 generic formula then the molecule and electron geometry of that molecule is tetrahedral.
Bonded atoms
Lone pair
Generic formula
Hybridization
Molecular geometry
Electron geometry
1
0
AX
S
Linear
Linear
2
0
AX2
Sp
Linear
Linear
1
1
AXN
Sp
Linear
Linear
3
0
AX3
Sp²
Trigonal planar
Trigonal planar
2
1
AX2N
Sp²
Bent
Trigonal planar
1
2
AXN2
Sp²
Linear
Trigonal planar
4
0
AX4
Sp³
Tetrahedral
Tetrahedral
3
1
AX3N
Sp³
Trigonal pyramid
Tetrahedral
2
2
AX2N2
Sp³
Bent
Tetrahedral
1
3
AXN3
Sp³
Linear
Tetrahedral
3
2
AX3N2
Sp³d
T-shaped
Trigonal bipyramidal
The bond angle of CCl4 is 109.5º because electrons around carbon will repel each other giving molecular geometry of CCl4 tetrahedral. Hence its bond angle is 109.5º approx.
Cabon tetrachloride polarity: Is CCl4 polar or nonpolar?
Is CCl4 polar or nonpolar? CCl4 is a non-polar molecule due to its symmetrical structure but the four bonds of CCl4 are polar because of the electronegativity difference between carbon and chlorine.
Let’s understand whether CCl4 is polar or non-polar in detail.
Three factors that indicate the polarity of CCl4
1. Electronegativity:
Electronegativity of atoms shows its tendency to electrons to itself. Greater the difference of electronegativity between atoms higher is the polarity between those atoms. The electronegativity of carbon is 2.5 and for chlorine, it is 3.0. Hence it results in the polar covalent bond.
But the bond polarity between all carbon and chlorine(C-Cl) is canceled due to the CCl4 symmetric tetrahedral shape.
Therefore CCl4 molecule becomes non-polar in nature because symmetry cancels out the individual polar vectors.
2. Dipole moment
Dipole moment ensures the strength of polarity between carbon and a chlorine atom. The net dipole moment of CCl4 is zero because opposite bond moments cancel out each other.
As chlorine is more electronegative than carbon. Therefore, chlorine attracts electrons towards itself. Hence the dipole is generated between the Carbon and Chlorine atom.
As you see in the above diagram, a dipole is generated between carbon and chlorine atoms. And the direction of all dipoles is the same from carbon to chlorine and at an equal distance.
As a result, equal charges are distributed in all directions.
So, they cancel each other dipole moment making CCl4 non-polar in nature.
3. Geometrical or molecular shape:
As we know molecular geometry of CCl4 is tetrahedral and all four bonds(C-Cl) are symmetrical with equal charge distribution making it easier to cancel out the dipole moment.
Also, there is no lone pair present on the central atom in the CCl4 lewis structure as a result no repulsion create along with the bond.
Therefore, the symmetrical nature of CCl4 ensures that all dipole moments are canceled out making CCl4 non-polar in nature.
Hence all these factors show that why Carbon tetrachloride CCl4 is nonpolar.
What is the formal charge in the CCl4 lewis dot structure and how to calculate it?
The formal charge in CCl4 shows that which atom(Carbon or chlorine) has a more positive or negative charge present on it.
To calculate the formal charge in Carbon tetrachloride lewis structure, Use the given formula-
Now we will calculate the formal charge on the central atom which is Carbon in the CCl4 Lewis structure.
⇒ Valence electron of Carbon = 4
⇒ Bonding electrons = 8
⇒ Non-bonding electrons(lone pairs electrons) = 0
Put these values in-formal charge formula-
∴ (4 – 0 – 8/2)
= 0 is the formal charge on the central atom(carbon).
FAQ
How many bonded pair and lone pair electrons present in the CCl4 lewis dot structure?
As per the CCl4 lewis structure, 0 lone pairs present around carbon atoms, and 4 bonded pairs present attached with chlorine
So, the total number of lone pair electrons = 0*2 = 0
and the total number of bonded pair electrons = 4*2 = 8
Why is CCl4 non-polar but its four bonds are polar?
As we discussed, four bonds of CCl4 are polar but the whole molecule is non-polar because the dipole moment generated in between carbon and chlorine canceled out due to the symmetrical tetrahedral shape of CCl4.
Also, there is no lone pair present on the central atom in the Carbon tetrachloride lewis structure which ensures that the molecular geometry of CCl4 is symmetrical with no repulsion in between the bonds.
Summary
It’s time for the quick revision of the CCl4 Lewis structure, molecular geometry, and other aspects which we have discussed in this article.
The total valence electron available for the CCl4 lewis structure is 32.
Carbon tetrachloride lewis structure is made up of one carbon atom that is situated at the middle position and four chlorine atoms that are at the surrounding position.
CCl4 molecular geometry is tetrahedral and its electron geometry is also tetrahedral.
The bond angle of CCl4 is 109.5º.
CCl4 is nonpolar in nature but its bond is polar.
The net dipole moment of Carbon tetrachloride is 0.
The formal charge in the CCl4 lewis dot structure is zero.
