Is ICl3 Polar or Nonpolar?
Iodine trichloride is an interhalogen compound of iodine and chlorine. Interhalogen compounds means those molecules which contain at least two different halogen atoms. They are more reactive than individual halogen atoms from which they are formed.
Iodine trichloride is an oxidizing agent which is capable of causing fire when in contact with organic materials.
Iodine trichloride is a bright yellow in color but when in exposure to light it can turn red due to the presence of elemental iodine.
So, is ICl3 (Iodine trichloride) polar or nonpolar molecule? The answer is yes. Iodine trichloride is a polar molecule. The molecular geometry of ICl3 looks very distorted and forms a T-shape with two lone pairs of electrons and is slightly symmetrical. The geometry of this polar bond has a dipole moment that does not cancel out each other which resulted in being a polar bond.
The chemical composition of ICl3 consists of iodine and chlorine.
The molecular mass of Iodine trichloride is 233.26 g/mol. It is calculated as below
Mol of ICl3 = 1*126.90 (mol mass of I) + 3*35.45 (mol mass of Cl) = 233.26 g/mol.
What are Polar and Nonpolar molecules?
There are two main divisions or classes of molecules which are polar molecules and nonpolar molecules. Polar means oppositely charged and nonpolar meaning equally charged.
Some molecules can be clearly and easily separable whether they are polar or nonpolar whereas some molecules fall in between the spectrum between both the classes.
Polarity is caused due to the polar bond formation between two elements that have different electronegativity which tends or makes the bonded electrons shift towards the high electronegative element which makes the bond as a partial negative and the other as a partial positive element.
In simpler words polarity refers to the distribution of electric charge around atoms, molecules or any other chemical groups.
Polar molecules occur when there occurs an electronegativity difference between the bonded atoms. Electronegativity is the measurement of how much an atom would want to bond with another atom.
Polar Molecules
Polar molecules occur when there is an electronegativity difference between the bonded atoms.
When the two atoms do not share electrons equally in a covalent bond the in such cases polar molecules occur. Similarly, a dipole is formed when there is a part of the molecule carrying a slight positive charge and the other part carrying a slight negative charge. This happens when there is a difference between the electronegativity values of each atom.
An extreme difference in the electronegativity forms an ionic bond where as a lesser difference in the electronegativity forms a polar covalent bond.
When the polar bonds do not share electrons equally; the negative charge from the electrons do not get evenly distributed in the molecule which causes a dipole moment.
We can look up the electronegativity on a table to find out whether the atoms are likely to form ionic bond or covalent bond
If the electronegativity difference between the two atoms is between 0.5 and 2.0 the atoms form a polar covalent bond and if the electronegativity difference between the atoms is greater than 2.0 the bond is considered to be ionic.
Some examples of polar molecules are:
- Water – H2O
- Ethanol – C2H6O
- Ammonia – NH3
- Hydrogen sulfide – H2S
- Sulfur dioxide – SO2
This type of bond is classified as a polar bond because this bond has a large electronegativity difference of 1.4.
Nonpolar Molecules
Nonpolar molecules occur when the electrons are evenly distributed in a covalent bond. When the molecules share electrons equally in a covalent bond the molecules do not get electrically charged.
In a nonpolar covalent the electrons are evenly distributed. We can predict nonpolar molecules will form when the atoms have the same or similar electronegativity. If the electronegativity difference between two atoms is less than 0.5 then the bond is considered nonpolar.
The only truly nonpolar molecules are those formed with identical atoms. Nonpolar molecules can also form when the atoms sharing a polar bond arranges in such a way that the electric charges cancel out each other.
In a nonpolar molecule there is no positive or negative poles formed in a molecule. Any charges are distributed evenly across the molecule and are generally symmetrical.
If the electronegativity difference between the two atoms is less than 0.5 the bond is considered as a nonpolar bond but whereas the only truly nonpolar molecules are hose formed with both identical bonds.
Some examples of nonpolar molecule are:
- Carbon dioxide- CO2
- Any noble gases like neon (Ne), argon (Ar), krypton (Kr), Xenon (Xe) and radon (Rn).
- Methane – CH4
- Benzene – C6H6
- Any of homonuclear diatomic elements: H2, N2, O2, CL2
- Hydrocarbon liquids, such as gasoline
- Most organic molecules
This type of bond is called a nonpolar bond because the electrons shared are equal and the electronegativity difference between the two atoms are usually zero.
Why is ICl3 a polar molecule?
When two atoms do not share electrons equally in a covalent bond then the polar molecule is formed. A polar bond is a type of covalent bond, a bond between two or more atoms is polar if the atoms have different electronegativities. These type of bond do not share electrons equally which means that the negative charge from the electrons do not get evenly distributed in the molecule.
This causes a dipole moment. When one end of the bond is positive and the other end is negative it can be known as a dipole moment.
Polar molecules are the molecules that has a charge on one side of the molecule which does not cancel out. One end of the molecule is slightly positive charged whereas the other end is slightly negative charged.
Polar solvents tend to dissolve polar solutes whereas nonpolar solvents tend to dissolve nonpolar solutes.
The electronegativity of iodine is 2.66 and chlorine is 3.16 which makes the difference between them to be 0.5
And since the electronegativity difference between the two atoms is between 0.5 and 2.0 the atoms is considered to be a polar covalent bond
Hence, Iodine trichloride is a polar molecule.
Is ICl3 Polar or Nonpolar?
Electronegativity difference:
Electronegativity in simpler terms is the measurement of how much an atom would want to bond with another atom. The electronegativity increases from left to right.
When atoms have a higher electronegativity value than its bonding atoms they do not share the centralized pair of electron. Which means that the shared electrons in a bond get less close to the atoms having higher value.
If the electronegativity difference between two atoms is between 0.5 to 2.0 it is considered as a polar bond.
In ICl3 molecule,
Electronegativity value of iodine = 2.66
Electronegativity value of chlorine = 3.16
Difference of electronegativity value between iodine and chlorine = 3.16 – 2.66 = 0.5
Since, the electronegativity difference between iodine and chlorine is 0.5 it makes this bond a polar molecule.
Lewis structure/ Molecular geometry:
A molecule is considered polar when the arrows of different length and if the arrows do not balance each other forming an asymmetrical shape.
The central atom is iodine, which gets bordered on three terminals with chlorine atoms more like in distorted T-shape or trigonal bipyramidal.
The molecules in Iodine trichloride are arranged in an unsymmetrical polarity order around the trigonal bipyramidal molecular geometry, giving rise to the molecular shape.
As the ICl3 molecule has a distorted t-shaped there occurs an electrical repulsion between the lone pairs of electrons in chlorine and the three bond pairs (I-Cl).
The Lewis structure of ICl3 gets dot electron representative structure. The valence electrons of atoms undergoes orbital mixing in the chemical reaction gives it a new type of molecular species. These molecules are nothing but a bundle of valence electrons formed from the atoms, but is converted to bond pairs and lone pairs in the molecular structure.
Dipole Moment:
A molecule with two poles is known as dipole. When a separation of charge occurs a dipole moment. A dipole moment can occur when between two ions in an ionic bond or between two atoms in an ionic bond. This moment can arise from the differences in between electronegativity.
This moment is a primary factor for any molecule being polar or nonpolar. Molecules that have zero dipole moments can be known as nonpolar molecule whereas having net dipole moments can be considered as a polar molecule.
The net dipole moment can be known as the product of dipole charge and the density between the atoms, higher than the electronegativity difference between the atoms the higher the net dipole moment would cause a higher partial charge.
Electron Density:
Electron density can be defined as the probability of the shared pair of electrons to be present at the dedicated position within the molecule.
In simpler terms electron density can be known as the measurement of the probability of an electron which is present at an element of space surrounding at any given point.
The electrons are closer to Iodine trichloride is a polar molecule. The molecular geometry of ICl3 looks much distorted and forms a T-shape with two lone pairs of electrons and is slightly symmetrical. The geometry of this polar bond has a dipole moment which does not cancel out each other which resulted in being a polar bond.
Solubility Principle:
According to the principle of solubility which states that “likes dissolves in likes” which means that polar molecules dissolves in polar solvent. Whereas nonpolar molecules dissolves in nonpolar solvents.
In simpler words, solubility is the quantity of a substance that can get completely dissolved in a given amount of solvent.
As ICl3 being a polar molecule it dissolves in polar solvents like water.
Properties of Iodine trichloride
- Iodine trichloride has a molecular weight of 233.26 g/mol.
- It is yellow/ brownish needle like in structure or fluffy powder.
- It has an irritating odor.
- Very corrosive to human skin.
- It should be stored at 20֯
- It has a density of 3.12 g/cm3 (20֯c)
- Iodine trichloride decomposes in water and other soluble alcohol or benzene.
- It is very light sensitive.
- Iodine trichloride is soluble with decomposition.
Uses of Iodine trichloride
- Iodine tricloride can be used as chlorinating agent.
- ICl3 can be used as an oxidizing agent.
- Iodine trichloride used as a topical antiseptic
- It can be used as a laboratory agent.
Conclusion
A polar bond is a type of covalent bond. A bond between two or more atoms are polar if the atoms have significant different electronegativities. The electrons in the polar bonds are not shared equally. Which further causes a dipole moment.
In ICl3 being an interhalogen compound it is more reactive than chlorine and iodine molecule to the electronegativity difference between the two atoms.
The geometry of Iodine trichloride is trigonal bipyramidial having a T-shape molecular shape. It has three bond pairs of electron ans two lone pairs of electrons. Both the electrons occupy the equatorial positions to achieve stability and minimize bond pair.
This hybridization of the iodine atom in the ICl3 causes trigonal bipyramidial geometry. Hence, this trigonal bipyramidial geometry and electronegativity difference between the chlorine and iodine atom gives off the nature of ICl3.
