Nitrogen trichloride is a chemical compound with its chemical formula as NCl3. its systematic IUPAC name is trichloramine. It is an oily and yellow colored liquid pigment. It has a pungent smell and an explosive liquid. Many students may have a query regarding whether NCl3 is polar or not. In this article, we will discuss this and will cover its properties and applications.
So, Is NCl3 Polar or Nonpolar? NCl3 is a slightly polar molecule because of the small difference between the electronegativity of nitrogen and chlorine atom. NCl3 molecule has one lone pair that leads to repulsion between electrons and the shape of the molecule is trional pyramidal.
Nitrogen trichloride is a yellow oily liquid with its pungent odor. This is mainly formed as a by-product when chlorine is treated with the ammonia derivative compounds.
The molecular mass of Nitrogen trichloride is calculated as below
Mol mass of NCl3 = 1 * 14 (mol mass of N) + 3 * 35.45 (mol mass of Cl) = 120.365 g/mol.
If we talk about the chemical composition of the NCl3 molecule, it consists of 1 Nitrogen atom (central atom) and three Chlorine atoms.
The chlorine atoms surround the nitrogen atom to get covalently bonded with it.
The valence electrons in the outermost shell of Nitrogen are 5 and that of chlorine is 7.
All the chlorine atoms share one electron from nitrogen to complete its octet leaving behind one lone pair on the nitrogen atom.
The electronegativity of Nitrogen is 3.04 and that of chlorine is 3.16. If we calculate the difference between their electronegativity, it comes out to be 0.12 ie; very less.
Due to this small difference between their electronegativity, the molecule is slightly polar. Some also consider it in the category of non-polar.
To be precise, it is slightly polar as chlorine being more electronegative tends to attract the bonded electrons with more influence as compared to nitrogen.
In this way, the polarity rises among the N-Cl bond. As a result, it also ensures some non zero dipole moment.
Similarly, all the bonds contribute to the dipole and the entire NCl3 molecule dipole moment value turns out to be 0.6 D.
What are Polar and Nonpolar Molecules?
The molecules are bonded by the types of forces ie; covalent, ionic, metallic, and hydrogen bonds.
Covalent bonds can be polar and nonpolar on the basis of various factors like electronegativity, dipole moment, and its shape.
Polar Molecules: The molecules that have non zero value of their dipole moment are polar molecules.
These molecules have unequal charge distribution on their atoms. The covalent bond formed between two atoms is said to be polar if the atoms differ in their electronegativity.
More electronegative atom attracts the bonded electron pairs slightly more towards itself and gains partial negative charge whereas the other gains partial positive charge.
In this way, the polarity in such bonds rises and dipole value also turns out to be non zero.
Few examples of such molecules are SO2, H2O. you can check out the reason for the polarity of SO2.
NonPolar Molecules: The molecules that have zero dipole moment are nonpolar in nature. These molecules have equal charge distribution on the atoms involved in the molecule.
Two atoms forming a covalent bond are said to be nonpolar if both atoms have equal value of electronegativity.
Both atoms share an equal proportion of bonded electron pairs. No poles (positive and negative) originate in such type of molecule.
Few examples of such molecules are SO3, Br2. You can check out the reason for the non-polarity of SO3.
Note: It is possible to have an existence of polar bonds in a nonpolar molecule, but due to symmetrical shape, these polarities get canceled with each other resulting in a nonpolar molecule.
Why is NCl3 a polar molecule?
Nitrogen trichloride is a chemical compound formed by nitrogen and chlorine atoms.
The electronegativity of Nitrogen and chlorine have a small difference of around (0.12 D) due to which the molecule is slightly polar
The chlorine atoms complete their octet by sharing one electron from nitrogen atom leaving behind one lone pair on the nitrogen atom.
As per VSEPR theory, the lone pair present on a molecule generates repulsive forces between lone pair and bond pairs.
As a result, the N-Cl bond faces a downward force, and the shape of the molecule turns to trigonal pyramidal.
The bond angle of Cl-N-Cl is around 107.1 degrees and the bond length of N-Cl is 1.759 A.
Being more electronegative, Chlorine atom attracts the bonded electron pair slightly towards it and gains a partial negative charge and nitrogen atom gains partial positive charge.
As a result, the dipole moment of N-Cl comes out to be non zero. Similarly, the entire NCl3 molecule results in the dipole moment value as 0.6D.
Factors affecting polarity of a molecule
Electronegativity: it is defined as the strength of an atom to attract the bonded pair of electrons towards it. More electronegative atom attracts the bonded pair of electrons slightly more towards its side and gains a partial negative charge.
A molecule having its atoms differing in electronegativity ensures its polarity. Greater the difference between the electronegativity of two atoms forming a covalent bond more is its polarity.
Therefore, the polarity of a molecule is directly proportional to the difference between the electronegativity of atoms.
Dipole Moment: it is the measure of the polarity of a molecule. Greater the value of the dipole moment of a molecule more is its polarity.
Technically, it is the product of charge on atoms and the distance between them. It is denoted by D and its SI unit is Debye.
D = Q * R
Geometrical Structure: The geometrical shape of an atom is an important parameter to check its polarity.
The molecule that is symmetric in shape is nonpolar whereas those whose shape is asymmetric (mainly because of lone pair) are polar in nature.
Properties of NCl3
- It exists as a yellow oily liquid at room temperature.
- The melting point of this compound is −40 °C or 233 K and its boiling point is.71 °C or 160 °F.
- The density of this compound is around 1.653 g/mL.
- Being a polar substance, it is soluble in substances like benzene, CS2, chloroform, CCl4, PCl3.
- It is immiscible in water and slowly decomposes.
- It has a pungent smell similar to that of chlorine.
Uses of NCl3
- Earlier it was used as a flour bleach, but no longer use in the United States.
- It can be used as an explosive material.
Nitrogen dichloride is a chemical compound having nitrogen and chlorine atoms that have a small difference between their electronegativity due to which it is a slightly polar molecule.
The three atoms of chlorine bonds with the nitrogen atom leaving behind a lone pair on the nitrogen atom.
As a result of the VSEPR theory, the shape of the NCl3 molecule turns to trigonal pyramidal.
So, due to these parameters, NCl3 is a slightly polar molecule.
Guys, if you have any questions regarding the polarity of NCl3, you can ask them in the comment section. We will reach out to you as soon as possible.