CHBr3 Molecular Geometry - Science Education and Tutorials

Q: What is the molecular notation for CHBr3 molecule?

CHBr3 molecular notation is AX4.

What is the molecular geometry of bromoform?. Drawing and predicting the CHBr3 molecular geometry is very easy by following the given method. Here in this post, we described step by step to construct CHBr3 molecular geometry. Carbon and bromine come from the 14th and 17th family groups in the periodic table respectively. Carbon has four valence electrons. bromine has seven valence electrons. Bromoform is a fluorinated hydrocarbon with three bromine in its composition.

Table of Contents

Key Points To Consider When drawing The CHBr3 Molecular Geometry

A three-step approach for drawing the CHBr3 molecular can be used. The first step is to sketch the molecular geometry of the CHBr3 molecule, to calculate the lone pairs of the electron in the central carbon atom; the second step is to calculate the CHBr3 hybridization, and the third step is to give perfect notation for the CHBr3 molecular geometry.

The CHBr3 molecular geometry is a diagram that illustrates the number of valence electrons and bond electron pairs in the CHBr3 molecule in a specific geometric manner. The geometry of the CHBr3 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 CHBr3 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 C-H and three C-Br bonds (dipole moment properties of the CHBr3 molecular geometry). The carbon-hydrogen and three carbon-bromine bonds in the bromoform(CHBr3), for example, are polarised toward the more electronegative value bromine atoms, and because all three (C-Br) bonds have the same size and polarity, their sum is nonzero due to the CHBr3 molecule’s bond dipole moment due to pulling the electron cloud to the downside in the tetrahedral geometry, and the CHBr3 molecule is classified as a polar molecule.

The molecule of bromoform(with tetrahedral shape CHBr3 molecular geometry) is tilted at 109.5 degrees bond angle of Br-C-H. It has a difference in electronegativity values between carbon, bromine, and hydrogen atoms, with bromine’s pull the electron cloud being greater than carbon’s. But bond polarity of C-Br is not canceled to each other in the tetrahedral geometry. As a result, it has no permanent dipole moment in its molecular structure. The CHBr3 molecule has no dipole moment due to an unequal charge distribution of negative and positive charges.

Overview: CHBr3 electron and molecular geometry

According to the VSEPR theory, the CHBr3 molecule possesses tetrahedral molecular geometry. Because the center atom, carbon, has three C-Br and one C-H bonds with the three bromine and one hydrogen atom surrounding it. The Br-C-H bond angle is 109.5 degrees in the tetrahedral CHBr3 molecular geometry. The CHBr3 molecule has a tetrahedral geometry shape because it contains three bromine and one hydrogen atoms.

There are three C-Br and one C-H bonds at the CHBr3 molecular geometry. After linking the three bromine and one hydrogen atoms and no lone pairs of electrons in the tetrahedral form, it maintains the tetrahedral structure. In the CHBr3 molecular geometry, the C-H and C-Br bonds have stayed in the four terminals and no lone pairs of electrons on the carbon atom of the tetrahedral molecule.

The center carbon atom of CHBr3 has no lone pair of electrons, resulting in tetrahedral CHBr3 electron geometry. However, the molecular geometry of CHBr3 looks like a tetrahedral and has no lone pairs of electrons on the carbon of the CHBr3 geometry. It’s the CHBr3 molecule’s symmetrical geometry. As a result, the CHBr3 molecule is polar.

How to find CHBr3 hybridization and molecular geometry

Calculating lone pairs of electrons on carbon in the CHBr3 geometry:

1.Determine the number of lone pairs of electrons in the core carbon atom of the CHBr3 Lewis structure. Because the lone pairs of electrons on the carbon atom are mostly responsible for the CHBr3 molecule geometry distortion, we need to calculate out how many there are on the central carbon atom of the CHBr3 Lewis structure.

Use the formula below to find the lone pair on the carbon atom of the CHBr3 molecule.
L.P(C) = V.E(C) – N.A(C-H and C-Br)/2

Lone pair on the central carbon atom = L.P(C)
The core central carbon atom’s valence electron = V.E(C)
Number of C-H and C-Br bonds = N.A (C-H and C-Br)
calculation for carbon atom lone pair in CHBr3 molecule.

For instance of CHBr3, the central atom, carbon, has four electrons in its outermost valence shell, three C-Br, and one C-H bond connection. This gives a total of four connections.

As a result of this, L.P(C) = (4 –4)/2=0

The lone pairs of electrons in the carbon atom of the CHBr3 molecule are zero.

Calculating lone pairs of electrons on bromine in the CHBr3 geometry:

Use the formula below to find the lone pair on the bromine atom of the CHBr3 molecule.
L.P(Br) = V.E(Br) – N.A(C-Br)

Lone pair on the terminal bromine atom = L.P(Br)
Terminal bromine atom’s valence electron = V.E(Br)
Number of C-Br bonds = N.A ( C-Br)
calculation for bromine atom lone pair in CHBr3 molecule.

For instance of CHBr3, three terminal atoms, bromine, have seven electrons in its outermost valence shell, one C-Br bond connection. This gives a total of three C-Br bond connections. But we are considering only one connection for the calculation.

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

The lone pairs of electrons in the bromine atom of the CHBr3 molecule are six. Three bromine atoms are connected with the central carbon atom.

Calculating lone pairs of electrons on hydrogen in the CHBr3 geometry:

Use the formula below to find the lone pair on the hydrogen atom of the CHBr3 molecule.
L.P(H) = V.E(H) – N.A(C-H)

Lone pair on the terminal bromine atom = L.P(H)
Terminal bromine atom’s valence electron = V.E(H)
Number of C-H bonds = N.A ( C-H)
calculation for hydrogen atom lone pair in CHBr3 molecule.

For instance of CHBr3, one terminal atom, hydrogen, has one electron in its outermost valence shell, one C-H bond connection. This gives a total of one C-H bond connection.

As a result of this, L.P(H) = (1 –1)=0

The lone pairs of electrons in the hydrogen atom of the CHBr3 molecule are zero. One hydrogen atom is connected with the central carbon atom.

In the CHBr3 electron geometry structure, the lone pair on the central carbon atom is zero. lone pairs of electrons in the bromine atom have six. Hydrogen contains none in the form of lone pair of electrons.

It means there are no lone pairs of electrons in the core carbon atom. No lone pair of electrons on the central carbon atom is responsible for the tetrahedral nature of CHBr3 molecular geometry. But in the structure bromine atoms are polarised downward in their geometry.

The hydrogen atom is placed at the top of the CHBr3 geometry. Because hydrogen atom is the lower electronegative value as compared with other atoms. Three bromine atoms are polarized towards the downside in the CHBr3 structure.

But in reality, the CHBr3 has no lone pairs of electrons in its structure. This makes the CHBr3 more stable in nature. Because there is no electric repulsion between bond pair and lone pair. But some sort of interaction is there between bromine lone pairs and bond pairs. But it is negligible.

Calculate the number of molecular hybridizations of the CHBr3 molecule

What is CHBr3 hybridization? This is a very fundamental question in the field of molecular chemistry. All the molecules are made by 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

CHBr3 molecule is made of one carbon, three bromine, and one hydrogen atoms. The carbon and bromine atoms have s and p orbitals. Hydrogen comes as the first element from the hydrogen family in the periodic table. The hydrogen atom has only s orbital.

When these atoms combine to form the CHBr3 molecule, its atomic orbitals mixed and form unique molecular orbitals due to hybridization.

How do you find the CHBr3 molecule’s hybridization? We must now determine the molecular hybridization number of CHBr3.

The formula of CHBr3 molecular hybridization is as follows:
No. Hyb of CHBr3= N.A(C-H and C-Br bonds) + L.P(C)
No. Hy of CHBr3= the number of hybridizations of CHBr3
Number of C-H and C-Br bonds = N.A (C-H and C-Br bonds)
Lone pair on the central carbon atom = L.P(C)
Calculation for hybridization number for CHBr3 molecule

In the CHBr3 molecule, carbon is a core central atom with three bromine and one hydrogen atom connected to it. It has no lone pairs of electrons on carbon. The number of CHBr3 hybridizations (No. Hyb of CHBr3) can then be estimated using the formula below.

No. Hyb of CHBr3= 4+0 =4

The CHBr3 molecule hybridization is four. The carbon and bromine atoms have s and p orbitals. The hydrogen atom has s orbital. The sp3 hybridization of the CHBr3 molecule is formed when one S orbital and three p orbitals join together to form the CHBr3 molecular orbital.

Molecular Geometry Notation for CHBr3 Molecule :

Determine the form of CHBr3 molecular geometry using VSEPR theory. The AXN technique is commonly used when the VSEPR theory is used to calculate the shape of the CHBr3 molecule.

The AXN notation of CHBr3 molecule is as follows:
The central carbon atom in the CHBr3 molecule is denoted by the letter A.
The bound pairs (three C-Br and C-H bonds) of electrons to the core carbon atom are represented by X.
The lone pairs of electrons on the central carbon atom are denoted by the letter N.
Notation for CHBr3 molecular geometry

We know that carbon is the core atom, with four electron pairs bound (three C-Br and one C-H) and zero lone pair of electrons. The general molecular geometry formula for CHBr3 is AX4.

According to the VSEPR theory, if the CHBr3 molecule has an AX4 generic formula, the molecular geometry and electron geometry will both be tetrahedral forms.

Name of Molecule	Bromoform or tribromomethane
Chemical molecular formula	CHBr3
Molecular geometry of CHBr3	Tetrahedral
Electron geometry of CHBr3	Tetrahedral
Hybridization of CHBr3	sp3
Bond angle (Br-C-H)	109.5º degree
Total Valence electron for CHBr3	26
The formal charge of CHBr3 on carbon	0

Summary:

In this post, we discussed the method to construct CHBr3 molecular geometry, the method to find the lone pairs of electrons in the central carbon atom, CHBr3 hybridization, and CHBr3 molecular notation. Need to remember that, if you follow the above-said method, you can construct the CHBr3 molecular structure very easily.