Best Overview: Is SCl2 Polar or Nonpolar? - Science Education and Tutorials

Sulfur compounds are very different in nature. Sulfur dichloride has the chemical formula SCl2. All atoms belong to the non-metal family group in the periodic table and possess a high electronegativity value. Students used to ask “Is SCl2 polar or nonpolar?”, “SCl2 Lewis Structure”, “SCl2 molecular geometry”, “SCl2 bond angle”, and “SCl2 polarity”. In this blog post, we are going to discuss the polarity of SCl2 in a detailed manner.

SCl2 is commonly appearing at ordinary temperatures and pressures, it exists as a liquid with a cherry-red texture. SCl2 contains one sulfur atom and two chlorine atoms. Sulfur dichloride (SCl2) is corrosive to biological tissue and metals, and it can also cause fires when it comes into contact with wood, cotton, and other materials. The sulfur atom stays the center of the molecule and the remaining two chlorine atoms. “Is SCl2 polar or nonpolar?”, to answer this question, we need a detailed analysis of the polarity of the SCl2 molecule.

Because of the bend V- type form of sulfur dichloride(SCl2). Chlorine has atomic number 17 in the modern periodic table and seven outermost valence shell electrons. It comes under the halogen family group. Similarly, Sulfur has atomic numbers 16 and six outermost valence shell electrons. Total electron counting, only one electron excess in chlorine as compared with sulfur.

SCl2 molecule is formed by elements of the oxygen and halogen family group in the periodic table. When SCl2 is exposed to air, it absorbs water quickly and produces white vapors that have a distinct odor and are toxic to breathe. Sulfur dichloride (SCl2) can generate sulfuric acid when it reacts with water and undergoes hydrolysis.

Is SCl2 polar or nonpolar, then? SCl2 (Sulfur Dichloride) is polar due to its bent geometrical shape caused by the presence of a lone pair on the sulfur atom. Second, the difference in electronegativity between sulfur and chlorine atoms causes the S-Cl bonds to become polar, causing the entire molecule to become polar as well, resulting in a net dipole moment of the SCl2 molecule is 0.54D.

Table of Contents

Preparation of SCl2

Sulfur dichloride(SCl2) is a bright cherry-red liquid with a strong intense odor. It is created primarily through the chlorination of sulfur. It is the heterogeneous reaction, sulfur in the solid phase and chlorine in the gas phase. Initially, sulfur reacted with chlorine gas formed an intermediate disulfur dichloride(S2Cl2). This first reaction step is exothermic in nature.

Disulfur dichloride (S2Cl2) undergoes further reaction with chlorine gas and gives sulfur dichloride(SCl2). The chemical thermodynamic equation of sulfur chlorination exothermic reaction is shown below.

S8 (solid phase)+ 4Cl2 (gas phase) —Exothermic—–> 4S2Cl2 ΔH(S2Cl2) = −58.2 kJ/mol
S2Cl2 (intermediate) + Cl2 (gas phase) —Exothermic——> 2SCl2 ΔH (SCl2) = −40.6 kJ/mol
Preparation of sulfur dichloride(SCl2)

SCl2 Molar Mass Calculation

SCl2 has a molecular mass of 102.97 gmol1, which may be computed as follows.

Mol mass of SCl2 = 1 * 32 (atomic mass of S) + 2 * 35.4 (atomic mass of Cl) = 102.97 g·mol−1.
SCl2 molar mass calculation

The chemical composition of the Sulfur dichloride molecule is 2 chlorine atoms and 1 sulphur atom in the middle.

SCl2 Lewis Structure: Is SCl2 polar or nonpolar?

The core atom is sulfur, which is flanked by two chlorine atoms. Sulfur contains six outermost valence electrons, which means it contains six electrons in its outermost shell, whereas Chlorine has seven outermost electrons. chlorine atom is required one electron to complete the octet of chlorine atoms. If you want to know about the octet rule, please see in our previous post.

As a result of this, both two chlorine atoms form covalent bonds with the sulfur atom, leaving the sulfur atom with two lone pairs. The bond pairs of S-Cl are repelled by the two lone pairs on the sulfur atom. According to VSEPR theory, electronic repulsion causes the molecule’s shape to bend (V-shape), similar to that of the water molecule.

The lone pair forces both two S-Cl bonds downward, resulting in the bent V-type form of the SCl2 molecule. Because they generate electrical repulsion among the SCl2 molecule, lone pairs have deformed shapes of the SCl2 molecule.

Electronegative difference calculation SCl2:

When it comes to the electronegativity value of the SCl2 molecule, Chlorine has an electronegativity of 3.16, while sulfur has an electronegativity of 2.58. The electronegativity difference can be calculated by the following method.

Electronegativity value of chlorine = 3.16
Electronegativity value of sulfur = 2.58
Difference of electronegativity value between sulfur and chlorine = 3.16 – 2.58=0.58
Electronegativity difference calculation of SCl2 molecule

The S-Cl bond of the SCl2 molecule becomes polar in nature due to this difference in electronegativity value. The power with which an atom can attract bound electron pairs towards its side is known as the electronegativity of the atom.

As a result of this, the dipole moment of the S-Cl bond is non zero, and the dipoles of both S-Cl bonds are not negated due to the V-shaped structure. The total dipole moment of the SCl2 molecule is calculated to be 0.54D. Sulfur atoms receive a partial positive charge on it, while chlorine atoms receive a partial negative charge on it.

SCl2 molecule’s electron dot structure is also known as SCl2 Lewis structure. It determines the number of outermost valence electrons and the electrons involved in the formation of the SCl2 molecule’s bonds. When discussing the Lewis structure of the SCl2 molecule, it is necessary to understand the outermost valence electrons of SCl2.

Sulfur is the middle element of the molecule, with 6 electrons in its outermost valence electron shell, while chlorine atom is the outermost valence electron shell, with 7 electrons and one electron missing in the shell to complete its octet.

As a result of this above explanation, the SCl2 molecule contains a total of 20 valence electrons. The two chlorine atoms establish covalent connections with the sulfur atom, leaving the sulfur atom with two lone pairs on it.

The lone pairs of sulfur atoms cause repulsion with S-Cl bond pairs, causing the S-Cl bonds to face downward force and the shape of the molecules to bend like that of the H2O (water) molecule. The Cl-S-Cl bond has a bond angle of roughly 103 degrees. S-Cl bond has a bond length of 201 pm (picometer).

To sketch the SCl2 Lewis structure by following these instructions:

Step-1: Determine the total number of outermost valence shell electrons in the SCl2 molecule. The first step is to figure out how many outermost valence shell electrons there are in the SCl2 Lewis structure. A valence electron is one of an atom’s outermost shell electrons. In the Lewis diagram, it is represented by dots. The central sulfur atom of the SCl2 molecule can be represented as follows

Look for the periodic group of each atom in SCl2 to determine its valence electron. Sulfur and chlorine are both members of the oxygen and halogen family, which is the 16th and 17th groups in the periodic table respectively. Chlorine and sulfur have seven and six valence electrons in their outermost shell respectively.

Because sulfur and chlorine belong to the oxygen and halogen family group in the periodic table, their valence electrons are six and seven respectively.

Total outermost valence shell electron of chlorine atom in SCl2 = 7
Total outermost valence shell electron of Sulfur atom in SCl2= 6
The SCl2 molecule has one central sulfur atom and two chlorine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for SCl2 Lewis structure( dot structure) = 6 + 7*2 = 20 valence electrons in SCl2
calculation of total valence electron of SCl2 molecule

Step-2: Locate the atom with the least electronegative charge and place it in the center of the SCl2 molecular geometry. In this phase, we’ll select the least electronegative atom in the SCl2 molecule to place in the Lewis structure diagram’s center. In the periodic table, the electronegativity value increases in order from left to right and decreases in order from top to bottom in periodic groups.

As a result, chlorine is the second atom in the halogen family group in the periodic table. Sulfur comes second in the oxygen family group. A sulfur atom has a lower electronegative value than a chlorine atom. Furthermore, because chlorine is the most electronegative element in chemistry, it can never be the central atom in a SCl2 Lewis structure diagram. As a result of this, place sulfur at the center of the SCl2 Lewis structure, with chlorine uniformly around it the V shape structure.

Step-3: Use two single bonds (S-Cl) to connect the outside and core atoms in the SCl2 molecule. Connect all outside atoms (Chlorine) to the core central atom (sulfur) with two single bonds in this stage.

Count how many outermost valence shell electrons we’ve used so far in the SCl2 structure. Because each Sulfur atom is connected to a chlorine atom by two single (S-Cl) bonds, each connection contains two electrons. Those is called bond pairs.

So, from the total of 20 valence electrons available for the SCl2 Lewis structure, we employed 4 electrons for two single (S-Cl) bonds in the SCl2 molecule. There are still 16 valence electrons left in the SCl2 molecule. Where do we need to place them in molecular geometry?

Step-4: Starting with the outer two chlorine atoms in the SCl2 molecule, place the remaining valence electrons. We always start inserting valence electrons from the exterior atom first in the Lewis structure diagram. As a result, first, wrap around the leftover valence electrons on each chlorine atom.

To complete its octet, chlorine requires 8 electrons in its outermost valence shell. With the help of a single bond, each chlorine already shares two electrons. Put 6 electrons around each chlorine atom and you’re done with the chlorine in SCl2 molecule.

In the SCl2 molecule structure above, we’ve put 12 electrons around the chlorine atoms, represented by a dot. As all chlorine atoms have 8 electrons in their outermost valence shell, each chlorine atom comfortably completes its octet stability in the SCl2 molecule.

Using the Lewis structure, count how many outermost valence shell electrons have been consumed so far. In the SCl2 molecular structure, 16 electrons are represented as dot structure, whereas two single bonds each contain 2 electrons. As an outcome of the calculation, the outermost valence shell electrons are 12 + 4 = 16.

So far, we’ve used 16 of the total 20 outermost valence shell electrons available for the SCl2 Lewis structure. But now the question is, “How to fix the remaining four valence electrons?”. We also have four valence electrons to spare in the SCl2 molecule.

Step-5: Complete central sulfur atom octet and use covalent bond if necessary. In the SCl2 Lewis structure, Sulfur is the central atom and it is connected with two single bonds (S-Cl) to the chlorine atoms. It means it already sharing 4 electrons with the help of 2 single bonds.

So, sulfur is obeying the rule of the octet as 8 electrons around it. Place the four remaining valence electrons around the sulfur center atom, which is acting as an octet stabilization in this case.

What are SCl2 electron and molecular geometry?

SCl2 has a V-shaped bent molecular geometry and water like electron geometry, according to the VSEPR theory. Because the core central atom, sulfur, has two S-Cl bonds with the surrounding two chlorine atoms. In the same plane, the Cl-S-Cl bond forms a 103-degree angle. Because two chlorine atoms are in the same plane, they form a V- type bent shape.

Above that plane, there are two lone pairs. It maintains the tetrahedral-like form after connecting the upper two lone pairs to the V-shaped bent form. The lone pair is located just opposite to bond pairs in the tetrahedral geometry. The two lone pairs of the electron are just above the V-shape bent bond pair plane in the tetrahedral geometry.

Because of the two lone pairs of electrons, it gives tetrahedral electron geometry. But the SCl2 molecular geometry is a V-shape bent form in nature. It is the asymmetrical geometry of the SCl2 molecule. That makes, SCl2 molecule is polar.

How to find SCl2 molecular geometry

Determine the number of lone pairs on the SCl2 Lewis structure’s core Sulfur atom.
We need to figure out how many lone pairs there are on the central sulfur atom of the SCl2 Lewis structure because the lone pairs on sulfur are primarily responsible for the SCl2 molecule geometry distortion.

Use the formula below to find the lone pair on the SCl2 molecule’s center Sulfur atom.
L.P(S) = V.E(S) – N.A(S-Cl)/2

Lone pair on the central sulfur atom = L.P(S)
The core central Sulfur atom’s valence electron = V.E(S)
Number of S-Cl bonds = N.A (S-Cl)
calculation for sulfur atom lone pair in SCl2 molecule

In the case of SCl2, the center atom, sulfur, has six outermost valence shell electrons and two chlorine atoms connected to it.

As a result of this, L.P(S) = (6 – 2)/2=2

The lone pair on the center sulfur atom of the SCl2 electron geometry structure is equal to two. It means, the central sulfur atom contains two lone pairs.

Determine the number of SCl2 molecular hybridizations.
How to find the hybridization of the SCl2 molecule?. Now we need to figure out what SCl2’s molecular hybridization number is.

The formula of SCl2 molecular hybridization is as follows:
No. Hyb = N.A(S-Cl) + L.P(S)
No. Hy= the number of hybridizations
Number of S-Cl bonds = N.A (S-Cl)
Lone pair on the central sulfur atom = L.P(S)
Calculation for hybridization number for SCl2 molecule

Sulfur, then, is a central atom with two chlorine atoms linked to it and two lone pairs in the SCl2 molecule. Then the number of hybridization (No. Hyb) can be calculated as follows

No. Hyb = 2+2 =4

Number of hybridization for SCl2 molecule is four. one S orbital, and three p orbitals combine together formed the sp3 hybridization.

3. Use VSEPR theory to determine SCl2 molecular geometry shape

When the VSEPR theory is utilized to calculate the shape of the SCl2 molecule, the AXN approach is typically used.

The AXN notation is as follows:
The center sulfur atom in the SCl2 molecule is denoted by the letter A.
The bound pairs (S-Cl) of electrons to the core atom are represented by X.
The lone pairs of electrons on the center sulfur atom are denoted by the letter N.
Notation for SCl2 molecular geometry

We know sulfur is the center atom with two bound (S-Cl) pairs of electrons and two lone pairs. because of the SCl2 Lewis structure. SCl2 has the general molecular geometry formula AX2N2.

If the molecule has an AX2N2 generic formula, the molecular geometry will be V- shape bent and the electron geometry will be tetrahedral, according to the VSEPR theory.

Name of Molecule	Sulfur dichloride
Chemical molecular formula	SCl2
Molecular geometry of SCl2	Bent V-shape
Electron geometry of SCl2	Tetrahedral
Hybridization	Sp³
Bond angle (Cl-S-Cl)	103º degree
Total Valence electron for SCl2	20
The formal charge of SCl2 on sulfur	0

How to calculate the formal charge in SCl2 Lewis Structure?

The formal charge on the sulfur central atom of the SCl2 molecule often represents the actual charge on that sulfur central atom. The formal charge will be found on the central sulfur atom of the SCl2 Lewis dot structure in the following calculation.

To calculate the formal charge on central sulfur atom of SCl2 molecule by using the following formula:
The formal charge on Sulfur atom of SCl2 molecule= (V. E(S)– L.E(S) – 1/2(B.E))
V.E (S) = Valence electron in sulfur atom of SCl2 molecule
L.E(S) = Lone pairs of an electron in sulfur atom of SCl2 molecule.
B.E = Bond pair electron in S atom of SCl2 molecule
calculation of formal charge on sulfur atom in SCl2 molecule

We have 6 valence electrons, 4 lone pair electrons, and four bonding electrons in the sulfur central atom (two single bonds attached to chlorine) of the SCl2 molecule. Now put these value of the sulfur atom in the above formula

Formal charge on sulfur atom of SCl2 molecule = (6- 4-(4/2)) =0

The formal charge on central sulfur atom of SCl2 Lewis structure is zero.

Lewis structure of some other related post in this blog. See more detail by clicking on it, H2O, BeCl2, SF4, NH3, XeF4, BF3, BrF3, BrF5, SO3, and CH2Cl2 molecules.

Dipole moment of SCl2

The dipole moment of the molecule can assist us in determining the polarity’s strength. The polarity of any molecule is proportional to its dipole moment. Because the form of SCl2 is asymmetric. The dipole moment of SCl2 does not cancel each other as a result of this.

Dipole moment of SCl2 can be calculated as follows
D(S-Cl) = Q(S-Cl) * R(S-Cl)
D(S-Cl) = Dipole moment of S-Cl bond in SCl2 molecule
Q(S-Cl) = Charge distribution in S and Cl atom of SCl2 molecule
R(S-Cl)= Bond length of S-Cl bond in SCl2 molecule
Dipole moment calculation of SCl2 molecule

Net dipole moment of SCl2 molecule is 0.54 D.

Why is SCl2 a polar molecule?

Due to the existence of two lone pairs on the Sulfur atom, the Sulfur dichloride (SCl2) molecule has a twisted V- shape bent form. According to the VSEPR hypothesis, lone pairs and bond pairs repel each other, causing the S-Cl bonds to move the lower side of the molecular structure, resulting in a V-shaped molecule.

The dipole moment of S-Cl bonds does not cancel out as it does in asymmetric SCl2 molecules. SCl2 has a dipole moment of 0.54D across the entire molecule. The formation of a polar molecule is caused by the geometrical structure and the difference in electronegativity value of atoms in the SCl2 molecule.

Because of the asymmetric shape of the SCl2 molecule, the charge is dispersed non-uniformly among the sulfur and chlorine atoms, resulting in the formation of positive and negative poles across the SCl2 molecule.

Properties of SCl2 molecule

The properties of SCl2 molecule are listed as follows

SCl2 is a bright red liquid with a strong odor.
The molecular mass of SCl2 is 102.97 g/mol.
SCl2 has a melting point of 121.0 °C (185.8 °F) and a boiling point of 59 °C (138 °F).
In the presence of water, it undergoes hydrolysis.
The refractive index of SCl2 is 1.5570.
The orbitals of the SCl2 molecule have sp3 hybridization.
This liquid has a density of roughly 1.621 g/cm3.
This compound’s auto ignition at the temperature of 234 °C.

Uses of SCl2 molecule

SCl2 molecule uses are listed as follows

SCl2 is a chlorinating agent that’s utilized in the chlorination process.
Insecticides and synthetic rubbers are also manufactured with it.
SCl2 is used to harden softwoods in the wood sector.

Conclusion

Due to the existence of two lone pairs on the central sulfur atom, sulfur dichloride has a bent V-shape form. With a bond angle(Cl-S-Cl) of roughly 103 degrees, the sulfur atom is the center atom, surrounded by two chlorine atoms. Its electron geometry is tetrahedral. The molecular hybridization of the SCl2 molecule is sp3.

Because of the difference in electronegativity between sulfur and chlorine atoms, the S-Cl bond is polar, and the entire molecule has a dipole moment of 0.54 D. This is due to the unsymmetrical structure of the SCl2 molecule with two lone pairs in a central sulfur atom. The SCl2 molecule is polar due to its asymmetric geometrical shape and unequal electronegativity of its atoms.

If you have any queries and doubts about this post, please leave your question in the comment section. We shall reply back on it as soon as possible.

FAQ on “Is SCl2 polar or nonpolar?”

what type of bond is SCl2?

Polar covalent bond

Is SCl2 polar and why?

The dipole moment of S-Cl bonds does not cancel out like it does in asymmetric SCl2 molecules. SCl2 has a dipole moment of 0.54D across the entire molecule. The formation of a polar molecule is caused by the geometrical structure and the difference in electronegativity value of atoms in the SCl2 molecule.

Is SCl2 a bent molecule?

Yes, Due to the existence of two lone pairs on the Sulfur atom, the Sulfur dichloride (SCl2) molecule has a twisted V- shape bent form. According to the VSEPR hypothesis, lone pairs and bond pairs repel each other, causing the S-Cl bonds to move lower side of molecular structure, resulting in a V-shaped molecule.