OCl2 lewis structure, molecular geometry, polar or nonpolar, bond angle, hybridization
Oxygen dichloride has the chemical formula OCl2 with a molar mass of 86.9054g/mol. It appears as brownish-yellow gas. It is soluble in water.
In this article, we will discuss OCl2 lewis structure, molecular geometry, bond angle, polar or nonpolar, its hybridization, etc.
Oxygen dichloride is a member of the chlorine oxide family of compounds. Its structure is very similar to water, its bond angle is larger than a water molecule.
OCl2 lewis structure is made up of one oxygen (O) atom and two chlorine (Cl) atoms. The oxygen (O) is in the central position, and chlorine (Cl) atoms are on either side of it. The lewis structure of OCl2 contains 8 lone pairs(2 lone pairs on oxygen (O) atom and 3 lone pairs on each chlorine (Cl) atom.
Follow some steps for drawing the Lewis dot structure for OCl2
1. Count total valence electron in OCl2
In the first step, you need to find how many valence electrons are present in the OCl2 molecule. As oxygen belongs to the 16th group in the periodic table and chlorine is in the 17th group.
∴ Total valence electrons available for drawing the OCl2 lewis structure = 6 + 7(2) = 20 valence electrons [∴ OCl2 molecule contains one oxygen and two chlorine]
2. Find the central atom
The central atom is usually the atom with the lowest subscript in the molecular formula.
So, in the OCl2 molecule, the chlorine atom has 2 subscripts, and oxygen has 1 subscript, hence, oxygen has the lowest subscript, therefore, it is the central atom and chlorine is an outer atom in the lewis diagram.
3. Connect outer atoms to the central atom with a single bond
In this step, we simply connect each outer atom(chlorine) to the central atom(oxygen) with the help of a single bond.
Now count the valence electron used in the above structure. A single bond means two electrons, in the above structure, two single bonds are used.
Therefore, (2 single bonds × 2) = 4 valence electrons are used in the above structure from the total of 20 valence electrons available for drawing the lewis structure of OCl2.
∴ (20 – 4) = 16 valence electrons
So, we are left with 16 valence electrons more.
4. Place remaining electrons on outer atoms and complete their octet
In this step, we will put the remaining valence electron on the outer atom first for completing their octet. In an OCl2 molecule, the outer atom is chlorine. And it requires 8 electrons in its outer shell to complete the octet.
As you see in the above figure, we have placed the 6 electrons represented as dots around each outer atom(chlorine). This is because chlorine atoms already have 2 electrons(one single bond) in their outer shell.
Hence, it only requires 6 more electrons for completing the octet.
Now once again count the total valence electron in the above structure.
(2 single bond × 2 electrons + 12 electrons represented as dots) = 16 valence electrons are used in the above structure.
Remember, we had a total of 20 valence electrons available for drawing the lewis structure of OCl2, and in the above structure, we used 16 valence electrons.
So, we are left with (20 – 16) = 4 valence electrons more.
5. Complete the octet of the central atom
Oxygen is the central atom in the OCl2 molecule. And we have 4 remaining valence electrons, hence, put these remaining valence electrons over the Oxygen central atom.
If you look at the above structure, we see that all atoms(oxygen and chlorine) completed their octet comfortably as each of them has 8 valence electrons(electrons represented as dots + electrons in a single bond) in their outer shell.
Also, we used all 20 valence electrons that are available for OCl2.
Now we just need to check the stability of the above structure through 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 the stability of the lewis diagram.
To calculate the formal charge on an atom. Use the formula given below-
The molecular geometry of OCl2 is Bent. The central atom Oxygen (O) is bonded with two chlorine (Cl) atoms and it has 2 lone pairs as well which means, it is an AX2N2 type molecule, as per VSEPR theory, its molecular geometry or shape will be Bent, but electron geometry will be Tetrahedral.
A represent central atom
X represent the number of bonded atom to central atom
N represent the number of lone pair on central atom
According to VSEPR theory or chart, the AX2N2 type molecule forms bent molecular geometry and tetrahedral electron geometry.
Hybridization of OCl2
We can calculate the hybridization of OCl2 using the steric number formula given below:
∴ Steric number of OCl2 = (Number of bonded atoms attached to oxygen + Lone pair on oxygen atom)
As per the OCl2 lewis structure, the oxygen central atom is bonded with two chlorine atoms and contains 2 lone pairs as well.
∴ Steric number of OCl2 = (2 + 2) = 4
So, for the steric number of 4, we get the hybridization of OCl2 is Sp3.
The bond angle of OCl2
The bond angle of Cl-O-Cl in OCl2 is 110.9º, “it is slightly larger than normal, likely due to steric repulsion between the bulky chlorine atoms.”
Is OCl2 polar or non-polar? OCl2 is a polar molecule. This is because of the asymmetrical structure that causes uneven charge distribution which contributes to the nonzero dipole moment and makes this molecule (OCl2) polar in nature.
Also, the chlorine atom gets a positive charge because of its less electronegativity, and the oxygen atom gets a negative charge because of its high electronegativity.
The electronegativity for chlorine, it is 3.16, and for oxygen, it is 3.44.
The separation of positive and negative charges leads to the dipole moment in OCl2 and these dipole moments will not be canceled out because the shape of OCl2 is bent which is asymmetric, hence, there will some net dipole moment in the molecule, and this makes, OCl2 a Polar molecule.
How many bonding pairs and lone pairs are present in the lewis structure of OCl2?
Bonding pairs are the pair of electrons that are in a bond. A single bond has one bond pair means 2 bonding electrons.
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 OCl2 lewis structure, we see there are 2 single bonds means 2 bonding pairs, and there are 16 dots electrons means 8 lone pairs. [∴ 2 dot electrons means one lone pair).
So, in the OCl2 lewis structure, there are 8 lone pairs and 2 bonding pairs present.
Why the molecular geometry of OCl2 is Bent?
The molecular geometry of OCl2 is bent, because, of the presence of two lone pairs on the central atom which act as a repulsive force on bonding pairs, due to these, bonded atoms are pushed down in order to minimize repulsion, as a result, it shapes appears as Bent or V-shaped.
When mercury oxide reacts with chlorine gas, it produces, oxygen dichloride with the risk of mercury poisoning, therefore, this method is not safe as well it is very expensive.
⇒ 2Cl2 + HgO → HgCl2 + OCl2
The reaction of sodium carbonate with chlorine gas at 20 – 30ºC in presence of water produces sodium bicarbonate, sodium chloride, and oxygen dichloride.
⇒ 2Cl2 + 2Na2CO3 + H2O → OCl2 + 2NaHCO3 + 2NaCl
In another method, there is an absence of water with high heating approx 150-250 ºC, sodium carbonate reacts with chlorine gas produces oxygen dichloride along with carbon dioxide and sodium chloride.
⇒ 2Cl2 + Na2CO3 → OCl2 + CO2 + 2NaCl
Summary
The total valence electron available for drawing the OCl2 lewis structure is 20.
The steric number of the oxygen central atom in the OCl2 molecule is 4, thus, it forms Sp3 hybridization.
OCl2 is a polar molecule, its geometry is bent which is asymmetrical therefore, it will cause a non-zero dipole moment, which makes the OCl2 polar molecule in nature.
The molecular geometry or shape of OCl2 is Bent.
In the OCl2 lewis structure, a total of 8 lone pairs and 2 bond pairs are present.
Vishal Goyal is the founder of Topblogtenz, a comprehensive resource for students seeking guidance and support in their chemistry studies. He holds a degree in B.Tech (Chemical Engineering) and has four years of experience as a chemistry tutor. The team at Topblogtenz includes experts like experienced researchers, professors, and educators, with the goal of making complex subjects like chemistry accessible and understandable for all. A passion for sharing knowledge and a love for chemistry and science drives the team behind the website. Let's connect through LinkedIn: https://www.linkedin.com/in/vishal-goyal-2926a122b/
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