How to draw BrF3 Lewis Structure? - Science Education and Tutorials

Bromine trifluoride chemical formula is BrF3. Drawing BrF3 Lewis Structure is very easy to by using the following method. Here in this post, we described step by step method to construct BrF3 Lewis Structure. The bromine and fluorine elements come as the member of the halogen family group from the periodic table. The valence electrons in bromine and fluorine are seven. The branch of halogen chemistry is used to make chemicals reagents for fluorination reactions.

Table of Contents

Key Points To Consider When Drawing The BrF3 Electron Dot Structure

A three-step approach for drawing the BrF3 Lewis structure can be used. The first step is to sketch the Lewis structure of the BrF3 molecule, to add valence electrons around the bromine atom; the second step is to add valence electrons to the three fluorine atoms, and the final step is to combine the step1 and step2 to get the BrF3 Lewis Structure.

The BrF3 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the BrF3 molecule. The geometry of the BrF3 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose the BrF3 geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the three Br-F bonds (dipole moment properties of the BrF3 molecule). The bromine-fluorine bonds in bromine trifluoride(BrF3), for example, are polarised toward the more electronegative fluorine in BrF3 molecule, and because both bonds have the same size and located around three fluorine terminals of the trigonal bipyramidal with two lone pairs (in total four electron) on the bromine atom, their sum of dipole moment is nonzero due to the BrF3 molecule’s bond dipole moment and more electron polarity to the fluorine atoms. Because each three Br-F bonds polarity not canceled each other in the BrF3 molecule. The trifluoro bromine or bromine trifluoride(BrF3) molecule is classified as a polar molecule.

The molecule of bromine trifluoride (with trigonal bipyramidal molecular geometry) is tilted, the bond angles between bromine and fluorine are 86.2 degrees. It has a difference in electronegativity values between bromine and fluorine atoms, with central bromine’s pull being less than terminal fluorine’s in the BrF3 molecule. But they canceled each other due to the asymmetrical molecular geometry of the BrF3 molecule.

As a result, it has the nonzero dipole moment. The BrF3 molecule has a nonzero dipole moment due to an unequal charge distribution of negative and positive charges. But both these atoms fall on the halogen family group. The fluorine atom is a more electronegative value than bromine in the BrF3 molecule. The net dipole moment of the BrF3 molecule is 1.19 D.

Molecules can be classified as polar or nonpolar. The molecule polar behaves in a different manner as compared to nonpolar.

Overview: BrF3 Lewis Structure

The central atom is bromine, which is bordered on three terminals with fluorine atoms( in distorted T-shaped or trigonal bipyramidal), and two lone pairs on the central in the trigonal bipyramidal geometry. Bromine has seven outermost valence electrons, indicating that it possesses seven electrons in its outermost shell, whereas fluorine also has seven valence electrons in its outermost shell. To complete the octet of the bromine and fluorine atoms requires one valence electron on each of their outermost shell.

Three fluorine atoms establish covalent connections with the central bromine atom as a result, leaving the bromine atom with two lone pairs. There are two lone pairs of electrons on the bromine central atom that resists the bond pairs of the three Br-F. According to VSEPR theory, the Br-F bond pairs polarity lead the BrF3 molecule to take on the distorted T-Shape or trigonal bipyramidal geometry structure.

The BrF3 molecule’s three Br-F bonds are arranged in unsymmetrical polarity order around the trigonal bipyramidal molecular geometry, giving rise to the BrF3 molecular shape. The BrF3 molecule has a distorted T- shaped or trigonal bipyramidal molecular geometry because there is electrical repulsion between the lone pairs of electrons in fluorine and three bond pairs(Br-F) of the BrF3 molecule.

Lewis structure of BrF3 has dot electron representative structure. Valence electrons of atoms undergo orbitals mixing in the chemical reactions, gives new types of molecular species. The molecule is nothing but a bundle of valence electrons from the atoms. But it is converted to bond pairs and lone pairs in the molecular structure.

Electronegative value Difference Calculation of BrF3 Molecule:

Bromine and Fluorine Electronegative difference in BrF3:

The bromine atom has an electronegativity of 2.96, while fluorine has an electronegativity of 3.98 in the BrF3 molecule. The difference in electronegativity of bromine and fluorine can be estimated using the method below.

The electronegative value difference between bromine and fluorine
Electronegativity value of bromine = 2.96
Electronegativity value of fluorine= 3.98
Difference of electronegativity value between bromine and fluorine= 3.98 – 2.96=1.02
Electronegativity difference between Br-F bond calculation of BrF3 molecule

The electronegative difference between bromine and fluorine is greater than 0.5. This indicated the bond polarity moves near to polar nature. Br-F bond polarity in the BrF3 molecule is polar.

Because of this difference in electronegativity of bromine and fluorine atoms, the BrF3 molecule’s Br-F bond becomes polar. The total net dipole moment of the BrF3 molecule is nonzero due to the no cancellation of the bond dipole moment in the distorted T-shaped or trigonal bipyramidal geometry. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of BrF3 is discussed in our previous post.

As a result, the Br-F bond’s dipole moment is high due to the polarization of the bonds and two lone pairs of electrons on bromine, and all Br-F bonds’ dipoles are arranged in the asymmetrical BrF3 molecular geometry. The BrF3 molecule’s total dipole moment is predicted to be 1.19 D.

The electron dot structure of the BrF3 molecule is also known as the BrF3 Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the BrF3 molecule’s bond formation. The outermost valence electrons of the BrF3 molecule must be understood while considering the Lewis structure of the molecule.

The bromine atom is the middle element in BrF3 molecular geometry, with seven electrons in its outermost valence electron shell, whereas the fluorine atom has seven electrons in its outermost valence electron shell. The fluorine atom has seven valence electrons.

The BrF3 has a total of 28 valence electrons as a result of the foregoing above said reasoning. With the core central bromine atom, the three terminals with three fluorine atoms form covalent bonds, leaving the bromine atom with two lone pairs in the middle of distorted T-shaped or trigonal bipyramidal geometry.

Because lone pair on the terminal fluorine atom creates interaction with Br-F bond pairs(but it is negligible). The bond angle of the F-Br-F bond in the distorted T- shaped or trigonal bipyramidal molecular geometry is approximately 86.2 degrees. This angle is smaller than the CH4 molecule bond angle. The Br-F bond length is 175 pm(picometer).

To sketch the BrF3 Lewis structure by following these instructions:

Step-1: BrF3 Lewis dot Structure by counting valence electrons on the bromine atom

To calculate the valence electron of each atom in BrF3, look for its periodic group from the periodic table. The halogen group families, which are the 17th group in the periodic table, are both made up of bromine and fluorine atoms. In their outermost shells, fluorine and bromine have seven valence electrons.

Calculate the total number of valence electrons in the BrF3 molecule’s outermost valence shell. The first step is to determine how many electrons are in the BrF3 Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the BrF3 Lewis diagram. The BrF3 molecule’s core bromine atom can be represented as follows:

Total outermost valence shell electron of bromine atom in BrF3= 7
Total outermost valence shell electron of fluorine atom in BrF3= 7
The BrF3 molecule has one central bromine and three fluorine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for BrF3 Lewis structure( dot structure) = 7+3*7=28 valence electrons in BrF3.
calculation of total valence electron of BrF3 molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of BrF3. We’ll choose the least electronegative value atom in the BrF3 molecule to place in the center of the BrF3 Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

The first step is to put seven valence electrons around the bromine atom as given in the figure.

Step-2: Lewis Structure of BrF3 for counting valence electrons around the terminal fluorine atoms

As a result, bromine is the first atom in the periodic table’s halogen family group. Fluorine is the first member of the halogen family. The electronegative value of the fluorine atom is higher than that of the bromine atom in the BrF3 molecule. Furthermore, fluorine has a seven electrons limit since bromine is the less electronegative element in the BrF3 molecule.

In the BrF3 Lewis structure diagram, the bromine atom can be the center atom of the molecule. As a result, central bromine in the BrF3 Lewis structure, with all three fluorine atoms arranged in distorted T-shaped or trigonal bipyramidal geometry.

Add valence electrons around the fluorine atom, as given in the figure.

Step-3: Lewis dot Structure for BrF3 generated from step-1 and step-2

Connect the exterior and core central atom of the BrF3 molecule with three single Br-F bonds. In this stage, use three fluorine atoms on the outside of the BrF3 molecule to the central bromine atom in the middle.

Count how many electrons from the outermost valence shell have been used in the BrF3 structure so far. Each Br-F bond carries two electrons because each bromine atom is connected to three fluorine atoms by three Br-F bonds. Bond pairings of Br-F are what they’re called.

So, out of the total of 28 valence electrons available for the BrF3 Lewis structure, we used 6 electrons for the BrF3 molecule’s three Br-F bonds. The BrF3 molecule has two lone pairs of electrons in the central bromine atom.

Place the valence electrons in the Br-F bond pairs starting with the core bromine, three fluorine atoms in the BrF3 molecule. In the BrF3 Lewis structure diagram, we always begin by introducing valence electrons from the central bromine atom(in step1). As a result, wrap around the central bromine atom’s bond pair valence electrons first (see figure for step1).

The bromine atom in the molecule gets only six electrons around its molecular structure. This central bromine atom is extra octet stable. But it has two lone pairs. Bromine(Br2) is a brownish liquid in nature. when bromine acted as brominating agent, it is used as a chemical reagent. But BrF3 is used as a fluorinating agent in organic chemistry.

Bromine requires 10 electrons in its outermost valence shell to complete the molecular extra octet stability, 6 electrons bond pairs in three Br-F bonds. Then lone pairs of electrons on the fluorine atoms of the BrF3 molecule are placed in a distorted T-shaped or trigonal bipyramidal geometry. Bromine already shares six electrons to the three Br-F bonds. Then place the valence electron in the fluorine atoms, it placed around seven electrons on each atom(step-2). 18 valence electrons placed around fluorine atoms as lone pairs of electrons.

We’ve positioned 18 electrons around the terminal fluorine atoms(step-3), which is represented by a dot, in the BrF3 molecular structure above. The bromine atom completes its molecular extra octet stability in the BrF3 molecule because it possesses six electrons in its (three Br-F) bond pairs with three fluorine in the outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the BrF3 Lewis structure. Three electron bond pairs are shown as dots in the BrF3 chemical structure, whereas three single bonds each contain two electrons. The outermost valence shell electrons of the BrF3 molecule(bond pairs) are six as a result of the calculation.

So far, we’ve used 28 of the BrF3 Lewis structure’s total 28 outermost valence shell electrons. Two lone pairs of electrons on the bromine atom in the distorted T structure or trigonal bipyramidal of the BrF3 molecule.

Complete the middle bromine atom stability and, if necessary, apply a covalent bond. The central bromine atom undergoes extra octet stability(due to two lone pairs of electrons).

The core atom in the BrF3 Lewis structure is bromine, which is bonded to the three fluorine atoms by single bonds (three Br-F). With the help of three single bonds, it already shares six electrons. As a result, the bromine follows the extra octet rule and has six electrons surrounding it on the three terminals of the BrF3 molecule’s trigonal bipyramidal geometry.

How to calculate the formal charge on bromine and fluorine atoms in BrF3 Lewis Structure?

Calculating formal charge on the bromine of BrF3 molecule:

The formal charge on the BrF3 molecule’s bromine central atom often corresponds to the actual charge on that bromine central atom. In the following computation, the formal charge will be calculated on the central bromine atom of the BrF3 Lewis dot structure.

To calculate the formal charge on the central bromine atom of the BrF3 molecule by using the following formula:
The formal charge on the bromine atom of BrF3 molecule= (V. E(Br)– L.E(Br) – 1/2(B.E))
V.E (Br) = Valence electron in a bromine atom of BrF3 molecule
L.E(Br) = Lone pairs of an electron in the bromine atom of the BrF3 molecule.
B.E = Bond pair electron in Br atom of BrF3 molecule
calculation of formal charge on bromine atom in BrF3 molecule

The bromine core atom (three single bonds connected to three fluorine atoms ) of the BrF3 molecule has seven valence electrons, two lone pairs of electrons(four electrons), and six bonding pairing valence electrons. Put these values for the bromine atom in the formula above.

Formal charge on bromine atom of BrF3 molecule = (7- 4-(6/2)) =0

In the Lewis structure of BrF3, the formal charge on the central bromine atom is zero.

Calculating formal charge on the fluorine of BrF3 molecule:

The formal charge on the BrF3 molecule’s fluorine terminal atom often corresponds to the actual charge on that fluorine terminal atom. In the following computation, the formal charge will be calculated on the terminal fluorine atom of the BrF3 Lewis dot structure.

To calculate the formal charge on the terminal fluorine atom of the BrF3 molecule by using the following formula:
The formal charge on the fluorine atom of BrF3 molecule= (V. E(F)– L.E(F) – 1/2(B.E))
V.E (F) = Valence electron in a fluorine atom of BrF3 molecule
L.E(F) = Lone pairs of an electron in the fluorine atom of the BrF3 molecule.
B.E = Bond pair electron in F atom of BrF3 molecule
calculation of formal charge on fluorine atom in BrF3 molecule

The fluorine terminal atom of the BrF3 molecule has seven valence electrons, three lone pairs of electrons(six electrons), and two bonding pairing valence electrons. Put these values for the fluorine atom in the formula above.

Formal charge on fluorine atom of BrF3 molecule = (7- 6-(2/2)) =0

In the Lewis structure of BrF3, the formal charge on the terminal fluorine atom is zero.

Summary:

In this post, we discussed the method to construct the BrF3 Lewis structure. First, the valence electrons are placed around the bromine atom. Second, place the valence electron on the fluorine atoms. Finally, when we combined the first and second steps. It gives BrF3 Lewis structure. Need to remember that, if you follow above said method, you can construct molecular dot structure very easily.