Carbon disulfide (CS2) lewis dot structure, molecular geometry, bond angle, hybridization, electron geometry

Home CS2 lewis structure and its molecular geometry/shape

CS2 Lewis structure molecular geometry

Carbon disulfide is made up of one carbon and two sulfur having the chemical formula CS2. It is a neurotoxic colorless volatile liquid.

In this article, we will discuss Carbon disulfide (CS2) lewis structure, molecular or electron geometry, bond angle, hybridization, polar or nonpolar, etc.

Carbon disulfide has a foul smell. It is flammable and insoluble in water.

Name of MoleculeCarbon disulfide (CS2)
Bond angle180°
Molecular geometry of CS2Linear shape
Electron geometry of CS2Linear
HybridizationSp
NatureNon-Polar molecule
Total Valence electron in CS2 16
Total Formal charge in CS20

How to draw lewis structure of CS2?

CS2 Lewis structure is made up of one carbon (C) atom, and two sulfur (S) atoms. The carbon (C) atom is kept at the central position and the Sulfur (S) atom is on either side of it in the lewis diagram. In the CS2 lewis structure, there are a total of 4 lone pairs and 2 double bonds present.

Let’s see how to draw the lewis dot structure for CS2 with simple steps.

Follow some steps for drawing the Lewis dot structure for CS2

1. Count total valence electron in CS2

As we know, the lewis diagram is all about representing the valence electron of atoms within the molecule. Valence electrons are the outermost electron of an atom that can participate in the bond formation either by donating or accepting.

To find the total valence electron in CS2, look at the periodic group of carbon and sulfur atoms.

By looking at the periodic table, we come to know carbon belongs to 14 groups and sulfur belongs to the 16th group in the periodic table. Hence, carbon has 4 valence electrons and sulfur has 6 valence electrons.

Valence electron of Sulfur = 6          [∴ Periodic group of sulfur = 16 or 6A]

Valence electron of Carbon =         [∴ Periodic group of carbon = 14 or 4A]

Total valence electron available for drawing the CS2 lewis structure = 4 + 2*6 = 16 valence electrons             [∴ CS2 molecule has one carbon and two sulfur atoms]

Total valence electron in CS2 lewis structure

2. Find the least electronegative atom and placed it at center

Now we need to find which atom(Carbon or Sulfur) has the least electronegativity then place that atom in the center of lewis’s diagram. 

The electronegativity of the sulfur atom is 2.58 and for the carbon atom, it is 2.55

Clearly, the Carbon atom is less electronegative than Sulfur, therefore, place it at the center of the lewis diagram and put the sulfur atoms on either side of it.

central atom in cs2

3. Connect carbon and sulfur with a single bond

In the third step, we will start to draw the skeletal structure of CS2 by connecting the outer atom (Sulfur) to the central atom (Carbon) with the help of a single bond.

CS2 skeletal structure

By looking at the above diagram, we come to know that two single bonds are used that contain 4 electrons. (A single bond means 2 electrons)

So, we used 4 electrons from a total of 16 valence electrons that are available for drawing the Lewis structure of CS2.

∴ (16 – 4) = 12 valence electrons

Now we are left with 12 valence electrons.

4. Placed remaining valence electrons around the outer atom

As we are left with 12 valence electrons and we have to place these electrons around the outer atom(Sulfur) first to complete its octet rule.

“Octet rule show that atom is most stable when eight electrons present in its valence shell.”

So, sulfur needs 8 electrons around it for coming into the stable zone. Therefore, place the remaining valence electron around sulfur atoms first for completing their octet shell.

complete octet of outer atoms in cs2

So, look at the above diagram and see how many valence electrons we used till now and how many are left. Each sulfur has 8 electrons(6 dot electrons + 2 electrons in a single bond), therefore, sulfur atoms completed their octets comfortably.

In the above diagram, 16 valence electrons are used(6 on each sulfur atom + 4 electrons in form of two single bonds).

So, we are left with zero valence electrons.

5. Complete central atom octet and make multiple bonds if necessary

In this step, we have to complete the central atom(Carbon) octet.

As carbon needs 8 electrons to complete its octet shell but carbon has only 4 electrons(two single bonds) around it. (Look at 4th step structure).

therefore, the carbon atom needs 4 more electrons to complete its octet.

Also, we have no extra valence electrons left for completing the octet of carbon. So, to overcome this problem, we will take the help of sulfur lone pair electrons.

We will convert the one lone pair of each sulfur atom into a covalent bond.

Lewis dot structure for CS2 (Carbon disulfide)

Now look at the above structure and see if the atoms of the CS2 molecule, completed their octet or not.

The carbon central atom has 8 electrons in its valence shell, since, it connected with 2 double bonds. [∴ 1 double bond means 4 electrons].

Also, both sulfur atoms also have 8 electrons, as they are connected with one double bond means 4 electrons + 4 electrons represented as dots.

Yes, both atoms(Carbon and Sulfur) have completed their octet rule comfortably as each of them has 8 electrons in the outermost shell. 

Now just check the overall stability of the above CS2 Lewis structure with the help of the formal charge concept.

6. Check the stability with the help of a formal charge concept

“The lesser the formal charge on atoms, the better is the stability of the lewis structure.”

To calculate the formal charge on an atom. Use the formula given below-

formal charge formula for lewis diagram

We will calculate the formal charge for the 5th step structure.

For carbon atom:

⇒ Valence electrons of carbon = 4

⇒ Nonbonding electrons on carbon = 0

⇒ Bonding electrons around carbon (two double bonds) = 8

∴ (4 – 0 – 8/2) = 0 formal charge on the central carbon atom.

For sulfur atom

⇒ Valence electrons of sulfur = 6

⇒ Nonbonding electrons on sulfur = 4

⇒ Bonding electrons around sulfur (one double bond) = 4

∴ (6 – 4 – 4/2) = 0 formal charge on the sulfur atoms.

So, both atoms(carbon and sulfur) get a formal charge equal to zero.

CS2 Lewis structure

Carbon disulfide (CS2) lewis structure

Therefore, the above lewis dot structure of CS2 is better, appropriate, and most stable as the overall formal charge is zero.

What is the electron and molecular geometry of CS2?

The molecular geometry of CS2 is linear. Because the carbon (C) central atom has no lone pair and is attached to the two sulfur (S) atoms. So, there are two regions of electron density around the carbon central atom, based on VSEPR theory, it will acquire linear molecular geometry.

“A region of electron density means the group of bonding or nonbonding electrons that present around the atom.

The single bond, double bond, or even triple bond around the atom will be counted as one region”.

CS2 Molecular geometry or shape

The electron pair around the carbon central atom will repel each other and tried to go far from each other, they will take the position where repulsion becomes minimum between them.

According to the VSEPR theory, the central atom with two regions of electron density adopts a linear molecular geometry because repulsion is minimum in electron pairs at this position.

Hence, the molecular geometry or shape of CS2 appears linear

The electron geometry for CS2 is also linear. Since, the central Carbon (C) atom is surrounded by 2 regions of electron density, according to VSEPR theory, “the maximum distance two regions of electron density can get away from affords a geometry called Linear”.

CS2 electron geometry

We can also find the electron and molecular geometry of CS2 using the AXN method and VSEPR chart.

AXN method to determine the geometry of CS2

AXN is a simple formula that represents the number of the bonded atom and lone pair on the central atom to predict the shape of the molecule using the VSEPR chart.

According to AXN method-

  • A represents the central atom.
  • X represents the bonded pair of electrons to the central atom.
  • N represents the lone pair of electrons on the central atom

AXN notation for CS2 molecule:

  • A denotes the central atom, so, carbon is the central atom in CS2 molecule A = Carbon
  • X denotes the bonded atoms to the central atom, Carbon is bonded with two sulfur atoms. Therefore, X = 2
  • N represents the lone pair on the central atom, as per the CS2 lewis structure, the carbon central atom has zero lone pair. Hence, N = 0

So, the AXN generic formula for the CS2 molecule becomes AX2N0 or AX2.

According to the VSEPR chart, if any molecule has the AX2 formula then the molecule geometry of that molecule is linear and electron geometry is also linear.

Look at the VSEPR chart below to clear your doubts.

The electron geometry and molecular geometry for CS2 as per VSEPR

So, the molecular geometry or shape of the CS2 is linear and its electron geometry is also linear.

Hybridization of CS2

According to the VSEPR theory, a Steric number is used to determine the hybridization of an atom.

When the Steric number is equal to 2, then the hybridization of that atom is sp, and if it is equal to 3 then Sp²…..so on.

Steric numberHybridization
2Sp
3Sp²
4Sp³
5Sp³d
6Sp³d²

Note: Steric number = Hybridization number

The steric number is simply an addition of bonded atom to the atom and a lone pair present on that atom.

The formula for finding the steric number of atoms.

steric number to calculate hybridization

According to CS2 lewis’s structure, Carbon is the central atom that has zero lone pair on it and two Sulfur atoms are attached to it.

Therefore, Steric number = 0 + 2

∴ S.N. = 2

So, two steric number means carbon has Sp hybridization in the CS2 molecule.

You can also find the steric number of the Sulfur atom. Each sulfur in the lewis dot structure of CS2 has two lone pairs on it and is attached to 1 Carbon atom.

Steric number of Sulfur = 2 + 1

= 3 is the steric number, which means each sulfur has Sp² hybridization in the CS2 molecule.

hybridization of CS2

The bond angle of CS2

CS2 has a bond angle of 180º. In CS2, the carbon (C) central atom has no lone pair and is attached to two sulfur (O) atoms. Therefore, no distortion occurs around the central atom which makes it linear in shape that has a bond angle of 180º.

CS2 bond angle

Carbon disulfide polarity: Is CS2 polar or nonpolar?

Well, we know the polar molecule has some dipole moment because of unequal distribution of charges whereas the non-polar molecule has an equal distribution of charges that cause zero dipole moment because they cancel out each other due to the symmetrical shape of the molecule.

Is Carbon disulfide (CS2) polar or non-polar? CS2 is a non-polar molecule because it contains two bonds(C=S) that are arranged symmetrically. Due to this, the dipole moment generated on both sides along C=S cancels out each other making it a non-polar molecule.

FAQ

 How many lone pairs are present in the lewis structure of CS2?

Lone pairs are those represented as dots in the lewis diagram that do not take part in the formation of bonds and are also called nonbonding electrons.

By looking at the lewis structure of CS2, we see there is 8 dot electrons present(4 dot electrons on each sulfur), which means, a total of 4 lone pairs are present in the lewis structure of CS2.    [ 2 dot electrons means 1 lone pair].

lone pair in cs2 lewis structure

How many valence electrons are available for drawing the CS2 lewis dot structure?

⇒ Valence electron available for Carbon = 4

⇒ Valence electron available for Sulfur = 6

∴ Total Valence electron available for CS2 lewis dot structure = 4 + 2×6 = 16 electrons

Why electron and molecular geometry of CS2 are same?

Two types of geometry can be predicted with the help of VSEPR theory- (a). Electron geometry (b). Molecular geometry

Electron geometry considers all electrons(Bonding and Lone pair electrons) whereas molecular geometry considers only Bonding atoms to determine the geometry of any molecule.

As we know, the molecular geometry of CS2 is linear and electron geometry is also linear. 

Since there is no lone pair present on the central atom in the CS2 lewis dot structure. Therefore, both molecular and electron geometry predict the shape of CS2 with the help of bonded pair of electrons.

Hence, the molecular geometry and electron geometry of CS2 is the same.

Also Read:-

Properties and Uses of Carbon disulfide

  • It has a boiling point of 46.24 °C and a melting point of −111.61 °C.
  • It is soluble in benzene, oil, and ether.
  • It appears as a colorless liquid and has a strong disagreeable smell.
  • It is very harmful to the liver, skin, and kidneys.
  • It is commonly used in organic chemistry as a building block.
  • It is used as a soil disinfectant.
  • It is used in camphor and as a pesticide intermediate.

Reactions of Carbon disulfide

Carbon disulfide is directly prepared by carbon and sulfur at 800–1000 °C.

⇒ C + 2S → CS2

When carbon disulfide reacts with oxygen, it forms, sulfur dioxide and carbon dioxide.

⇒ CS2 + 3O2 → CO2 + 2SO2

Chlorination of CS2 forms carbon tetrachloride.

⇒ CS2 + 3Cl2 → CCl4 + S2Cl2

Summary

  • The total valence electron available for drawing the CS2 lewis structure is 16.
  • The molecular geometry of CS2 is Linear. It has a linear geometry arrangement like S=C=S. CS2 has 2 electron domains, resulting in a linear electron domain geometry.
  • In the CS2 lewis structure, there is a total of 4 lone pairs present. Two lone pairs on each sulfur atom.
  • The bond angle of CS2 is 180º. Since it is linear in shape with an arrangement like that S=C=S.
  • Two types of hybridization in CS2 – Sp, and Sp2.
  • The net dipole moment of CS2 is zero.
  • CS2 is a non-polar molecule.
  • The overall formal charge in CS2 is zero.

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