Oxygen difluoride is a chemical compound having its chemical formula as OF2. It was first reported in the year 1929. As per the VSEPR theory, the shape of the molecule is bent like that of a water molecule but have different properties. Many students might have a query about whether the OF2 molecule is polar or not. In this article, I will answer this question and will cover the surrounding topics too.
So, Is OF2 Polar or Nonpolar? OF2 (Oxygen difluoride) is polar in nature because of its bent shaped geometrical structure and difference between the electronegativity of Oxygen and Fluorine atoms. As a result, the dipole moment of the molecule turns out to be nonzero making the OF2 a polar molecule.
Oxygen difluoride is also known by its other name hypofluorous anhydride. It is a colorless gas in appearance at room temperature. It turns out to pale yellow colored liquid on condensation.
It is a foul-smelling substance. The melting point of oxygen difluoride( OF2) is around −223.8 °C or −370.8 °F.
If we talk about the chemical composition of OF2, it consists of 1 Oxygen atom and 2 fluorine atoms.
The electrons in the outermost shell of fluorine are 7 and that of oxygen is 6. The fluorine atom needs 1 electron and oxygen atom needs 2 electrons for their stabilization ie; to complete their octet.
Accordingly, the two fluorine atoms form a single covalent bond with an oxygen atom. And the molecules become stable leaving behind 2 lone pairs on oxygen atom and 3 lone pairs on both fluorine atoms.
The molar mass of the OF2 molecule is 53.9962 g/mol.
It is calculated as
Mol mass of OF2 = 1 * 16 (mol mass of O) + 2 * 19 (mol mass of F)
As per the VSEPR theory, the repulsion among lone pairs causes distortion in shape. Similarly, the OF2 molecule also has bent shape due to repulsion between lone pairs and bonded pairs of fluorine and oxygen atoms.
And the factor ‘electronegativity’ is important to determine the polarity of a molecule.
In the molecule of OF2, the fluorine is more electronegative than oxygen. The electronegativity of Fluorine is 3.98 and that of oxygen is 3.44.
The more electronegative atom attracts the bonded pair of electrons slightly towards itself and gains a partial negative charge.
What are Polar and Nonpolar Molecules?
The molecules are held together by the bonds. These bonds can be metallic, covalent, ionic, and hydrogen bonds.
Among these bond forces, the ionic and covalent bonds are strongest and majorly used in the chemical compounds.
A covalent bond can be polar as well as nonpolar depending upon the factors discussed below in detail.
Polar molecules: these are the molecules in which the net dipole moment of the molecule comes out to be nonzero.
The covalent bond formed between two atoms is said to be polar if the electronegativity of both atoms is not equal.
These atoms unequally share the bonded pair of electrons. The more electronegative atom gains partial negative charge and other atom gets a partial positive charge.
Examples of such molecules are SO2, OF2, etc. You can check out the reason for the polarity of SO2.
Nonpolar molecules: These are the molecules in which the net dipole moment is zero. The atoms forming a nonpolar covalent bond have the same electronegativity value.
These atoms share the bonded electrons equally such that equal charge is present on both of atoms. Examples of such molecules are CO2, H2, etc.
The main factors that determine the polarity of a molecule are electronegativity, geometrical shape, and dipole moment.
Note: It is possible to have the existence of a polar bond within a nonpolar molecule. Because due to symmetrical geometry the polarity is canceled by each other.
Why is OF2 a polar molecule?
The molecule of OF2 is polar in nature because of its bent shaped structure and difference between the electronegativity of oxygen and fluorine.
The geometrical shape of Oxygen difluoride is similar to that of water ie; V-shaped bent structure.
The OF2 molecule has oxygen and fluorine atoms that have an electronegativity difference of around 0.54 units.
Being more electronegative, the fluorine atom attracts the bonded pair of electrons slightly towards it and it gains a partial negative charge and oxygen atom gains partial positive charge.
As a result, the O-F bonds ensure the dipole moment in the same direction and the net dipole moment of the whole molecule is also nonzero.
There are 2 lone pairs on oxygen atom and 3 lone pairs on both fluorine atoms. As per the VSEPR theory, the repulsion among lone pairs and bond pairs causes the distortion in shape.
Therefore, the shape os OF2 is changed to bent shape.
The asymmetric geometrical structure of a molecule makes it polar because, in these shaped molecules, the dipoles do not cancel each other. They gave resultant dipole as nonzero.
Due to these factors, the OF2 molecule is a polar molecule.
Factors affecting polarity of a molecule
Electronegativity: The term ‘electronegativity’ is the strength of an atom to attract the bonded pair of electrons towards it. More electronegative atom attracts bonded electron pairs more towards itself.
The difference between the electronegativity of two atoms forming a covalent bond exhibit polarity in their bond.
Polarity is directly proportional to the difference between the electronegativity of the atoms.
Geometrical shape: If the shape of a molecule is symmetric, the molecule is nonpolar in nature because of the following reasons.
The symmetrically shaped molecules in which atoms have the same electronegativity have equal charge distribution on them and are nonpolar in nature.
If the symmetrical molecule has dipoles within it, then these dipoles get canceled by each other.
Therefore, symmetrically shaped molecules are nonpolar in nature.
Dipole moment: The dipole moment of a molecule is the measure of its polarity. The polarity of a molecule is directly proportional to the dipole moment of a molecule.
It is denoted by D.
Mathematically, it is the product of the charge and the distance between them.
Molecular structure of OF2
The molecular structure of a molecule depends upon the electronic configuration of the molecule.
In the molecule of OF2, there are 20 valence electrons out of which 4 electrons participate in the covalent bonds and remaining exist on the oxygen and fluorine atoms in the form of lone pairs.
There are 2 lone pairs present on the Oxygen atom and 3 lone pairs on each Fluorine atom.
As per VSEPR theory, due to the repulsion between lone pair and bond pairs the structure of the OF2 molecule becomes bent similar to the molecule of water (H2O).
The lone pairs exert force on the bonded pair electrons and bonds shift towards downward resulting in the V-shaped molecule OF2.
The bond angle in the OF2 molecule is 103 degrees.
Below is the geometrical structure of the OF2 molecule.
Lewis structure of OF2
Lewis structure of a molecule is the structure that depicts the bonding between the atoms and lone pairs on the atoms involved in the molecule
Lewis structure can be drawn for coordination compounds as well as covalent compounds.
It is also known as an electron dot diagram.
To determine the lewis structure of OF2, the following information is needed
Lone pair around central atom(Oxygen): 2
Lone pair around other atoms (Fluorine) : 3
Molecular geometry of molecule: Bent shape
Based on this information, the lewis structure can be drawn
Properties of OF2
- Oxygen difluoride exists as a colorless gas at room temperature.
- On condensation, it turns to pale yellow color liquid.
- The melting point of this compound is −223.8 °C or −370.8 °F. And the boiling point is around −144.75 °C or −228.55 °F.
- The vapor pressure of OF2 at a temperature of −58.0 °C is 48.9 atm.
- The density of OF2 in the gaseous state is 1.88 g/l at room temperature.
- This compound has its specific gravity 1.86 at room temperature.
Uses of OF2
- Oxygen difluoride is a strong oxidizer, so used to oxidize propellants.
- The oxidation property of OF2 has its great use in rocket fuel systems.
- This is also used as a biochemical solvent by the fictional form of lives present in the solar system.
The oxygen difluoride (OF2) has a bent molecular shape and also have lone pairs on Oxygen and Fluorine atoms.
As per VSEPR theory, the repulsion between lone pairs on oxygen and fluorine and bonded pairs causes the shape of OF2 to turn out to V-shape or bent shape.
The electronegativity of fluorine is more than that of oxygen due to which the O-F bond becomes polar.
This polarity in the O-F bond ensures some non zero dipole and due to asymmetric shape of OF2, the dipole of molecules comes out to be non zero making it a polar in nature.
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