IF3 Molecular Geometry - Science Education and Tutorials

Q: What is the molecular notation for IF3 molecule?

IF3 molecular notation is AX3N2.

Trifluoro iodine or iodine trifluoride(IF3) has the composition of one iodine and three fluorine atoms. What is the molecular geometry of iodine trifluoride?. Drawing and predicting the IF3 molecular geometry is very easy by following the given method. Here in this post, we described step by step to construct IF3 molecular geometry. Iodine and fluorine come from the 17th family group in the periodic table. Iodine or fluorine has seven valence electrons.

Table of Contents

Key Points To Consider When drawing The IF3 Molecular Geometry

A three-step approach for drawing the IF3 molecular can be used. The first step is to sketch the molecular geometry of the IF3 molecule, to calculate the lone pairs of the electron in the central iodine atom; the second step is to calculate the IF3 hybridization, and the third step is to give perfect notation for the IF3 molecular geometry.

The IF3 molecular geometry is a diagram that illustrates the number of valence electrons and bond electron pairs in the IF3 molecule in a specific geometric manner. The geometry of the IF3 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory) and molecular hybridization theory, which states that molecules will choose the IF3 geometrical shape in which the electrons have from one another in the specific molecular structure.

Finally, you must add their bond polarities characteristics to compute the strength of the three I-F bonds (dipole moment properties of the IF3 molecular geometry). The iodine-fluorine and three iodine-fluorine bonds in the iodine trifluoride(IF3), for example, are polarised toward the more electronegative value fluorine atoms, and because all three (I-F) bonds have the same size and polarity, their sum is nonzero due to the IF3 molecule’s bond dipole moment due to pulling the electron cloud to the downside in the trigonal bipyramidal geometry, and the IF3 molecule is classified as a polar molecule.

The molecule of iodine trifluoride(with trigonal bipyramidal shape IF3 molecular geometry) is tilted at 88.5 degrees bond angle of F-I-F. It has a difference in electronegativity values between iodine and fluorine atoms, with fluorine’s pull the electron cloud being greater than iodine’s. But bond polarity of I-F is not canceled to each other in the trigonal bipyramidal geometry. As a result, it has a permanent dipole moment in its molecular structure. The IF3 molecule has a dipole moment due to an unequal charge distribution of negative and positive charges.

Overview: IF3 electron and molecular geometry

According to the VSEPR theory, the IF3 molecule possesses trigonal bipyramidal molecular geometry. Because the center atom, iodine, has three I-F bonds with the three fluorine atoms surrounding it. The F-I-F bond angle is 88.5 degrees in the trigonal bipyramidal IF3 molecular geometry. The IF3 molecule has a trigonal geometry shape because it contains three fluorine atoms.

There are three I-F bonds at the IF3 molecular geometry. After linking the three fluorine atoms and two lone pairs of electrons in the trigonal bipyramidal form, it maintains the distorted T-shaped structure. In the IF3 molecular geometry, the I-F bonds have stayed in the three terminals and two lone pairs of electrons on the iodine atom of the trigonal bipyramidal molecule.

The center iodine atom of IF3 has two lone pairs of electrons, resulting in trigonal bipyramidal IF3 electron geometry. However, the molecular geometry of IF3 looks distorted T-shaped and two lone pairs of electrons on the iodine of the IF3 geometry. It’s the IF3 molecule’s symmetrical geometry. As a result, the IF3 molecule is polar.

How to find IF3 hybridization and molecular geometry

Calculating lone pairs of electrons on iodine in the IF3 geometry:

1.Determine the number of lone pairs of electrons in the core iodine atom of the IF3 Lewis structure. Because the lone pairs of electrons on the iodine atom are mostly responsible for the IF3 molecule geometry distortion, we need to calculate out how many there are on the central iodine atom of the IF3 Lewis structure.

Use the formula below to find the lone pair on the iodine atom of the IF3 molecule.
L.P(I) = V.E(I) – N.A(I-F)/2

Lone pair on the central iodine atom = L.P(I)
The core central iodine atom’s valence electron = V.E(I)
Number of I-F bonds = N.A (I-F)
calculation for iodine atom lone pair in IF3 molecule.

For instance of IF3, the central atom, iodine, has seven electrons in its outermost valence shell, three I-F bond connections. This gives a total of three connections.

As a result of this, L.P(I) = (7 –3)/2=2

The lone pairs of electrons in the iodine atom of the IF3 molecule are two.

Calculating lone pairs of electrons on fluorine in the IF3 geometry:

Use the formula below to find the lone pair on the fluorine atom of the IF3 molecule.
L.P(F) = V.E(F) – N.A(I-F)

Lone pair on the terminal fluorine atom = L.P(F)
Terminal fluorine atom’s valence electron = V.E(F)
Number of I-F bonds = N.A ( I-F)
calculation for fluorine atom lone pair in IF3 molecule.

For instance of IF3, three terminal atoms, fluorine, have seven electrons in its outermost valence shell, one I-F bond connection. This gives a total of three I-F bond connections. But we are considering only one connection for the calculation.

As a result of this, L.P(I) = (7 –1)=6

The lone pairs of electrons in the fluorine atom of the IF3 molecule are six. Three fluorine atoms are connected with the central iodine atom.

In the IF3 electron geometry structure, the lone pair on the central iodine atom is two. lone pairs of electrons in the fluorine atom have six. Three fluorine atoms have 18 lone pairs of electrons.

It means there are two lone pairs of electrons in the core iodine atom. Two lone pair of electrons on the central iodine atom is responsible for the trigonal bipyramidal nature of IF3 molecular geometry. But in the structure fluorine atoms are polarised sidewise in their geometry.

The two lone pairs of electrons are placed at another side of the IF3 geometry. Because the iodine atom is a lower electronegative value as compared with other atoms in the IF3 molecule. Three fluorine atoms are polarized towards the sidewise in the IF3 structure.

But in reality, the IF3 has two lone pairs of electrons in its structure. This makes the IF3 more irregular structure of the molecule. Because there is electric repulsion between bond pairs and lone pairs. But some sort of interaction is there between fluorine lone pairs and bond pairs. But it is negligible.

Calculate the number of molecular hybridizations of the IF3 molecule

What is IF3 hybridization? This is a very fundamental question in the field of molecular chemistry. All the molecules are made of atoms. In chemistry, atoms are the fundamental particles. There are four different types of orbitals in chemistry. They are named s, p, d, and f orbitals.

The entire periodic table arrangement is based on these orbital theories. Atoms in the periodic table are classified as follows:

s- block elements
p- block elements
d-block elements
f-block elements
Atoms are classified in the periodic table

IF3 molecule is made of one iodine, three fluorine atoms. The fluorine and iodine atoms have s and p orbitals. Fluorine comes as the first element from the halogen family in the periodic table. The iodine atom also belongs to the same family group. But it falls as the fourth element in the periodic table.

When these atoms combine to form the IF3 molecule, its atomic orbitals mixed and form unique molecular orbitals due to hybridization.

How do you find the IF3 molecule’s hybridization? We must now determine the molecular hybridization number of IF3.

The formula of IF3 molecular hybridization is as follows:
No. Hyb of IF3= N.A(I-F bonds) + L.P(I)
No. Hy of IF3= the number of hybridizations of IF3
Number of I-F bonds = N.A (I-F bonds)
Lone pair on the central iodine atom = L.P(I)
Calculation for hybridization number for IF3 molecule

In the IF3 molecule, iodine is a core central atom with three fluorine atoms connected to it. It has two lone pairs of electrons on iodine. The number of IF3 hybridizations (No. Hyb of IF3) can then be estimated using the formula below.

No. Hyb of IF3= 3+2 =5

The IF3 molecule hybridization is five. The iodine and fluorine atoms have s and p orbitals. The sp3d hybridization of the IF3 molecule is formed when one S orbital, three p orbitals, and one d orbital join together to form the IF3 molecular orbital.

Molecular Geometry Notation for IF3 Molecule :

Determine the form of IF3 molecular geometry using VSEPR theory. The AXN technique is commonly used when the VSEPR theory is used to calculate the shape of the IF3 molecule.

The AXN notation of IF3 molecule is as follows:
The central iodine atom in the IF3 molecule is denoted by the letter A.
The bound pairs (three I-F bonds) of electrons to the core iodine atom are represented by X.
The lone pairs of electrons on the central iodine atom are denoted by the letter N.
Notation for IF3 molecular geometry

We know that iodine is the core atom, with three electron pairs bound (three I-F) and two lone pairs of electrons. The general molecular geometry formula for IF3 is AX3N2.

According to the VSEPR theory, if the IF3 molecule has an AX3N2 generic formula, the molecular geometry and electron geometry will both trigonal bipyramidal forms.

Name of Molecule	Iodine trifluoride
Chemical molecular formula	IF3
Molecular geometry of IF3	Trigonal bipyramidal
Electron geometry of IF3	Trigonal bipyramidal
Hybridization of IF3	sp3d
Bond angle (F-I-F)	88.5º degree
Total Valence electron for IF3	28
The formal charge of IF3 on iodine	0

Summary:

In this post, we discussed the method to construct IF3 molecular geometry, the method to find the lone pairs of electrons in the central iodine atom, IF3 hybridization, and IF3 molecular notation. Need to remember that, if you follow the above-said method, you can construct the IF3 molecular structure very easily.