Boron trifluoride (BF3) is a poisonous, odorless, and colorless gas. When exposed to moist air, it emits a strong odor and produces white vapors. When breathed, boron trifluoride is extremely poisonous.
BF3 Lewis structure comprises two different atoms: Boron, and Fluorine and is a nonpolar molecule with bond angles of 120 degrees.
Boron trifluoride is utilized in the manufacture of various adhesives, lubricants, and other additives. It is also utilized as a catalyst in processes such as alkylation, esterification, and condensation.
Name of molecule | Boron Trifluoride (BF3) |
Bond Angles | 120 degrees |
Molecular Geometry of Boron trifluoride | trigonal planar |
No Valence Electrons in the BF3 molecule | 24 valence electrons |
BF3 Polar or Nonpolar? | Nonpolar |
BF3 Hybridization | sp2 type |
Following are the steps to construct the Lewis Structure.
Step-1: Count the valence electrons of atoms
To draw the Lewis structure, we need to figure out the number of valence electrons in individual atoms as shown in the table below.
Atom | Electronic Configuration | Valence Electrons (VEs) |
5B | 1s2 2s2 2p1 | 3 |
9F | 1s2 2s2 2p5 | 7 |
VEs= VEs in boron + VEs in fluorine
Valence electrons in BF3 = 3+3(7) = 24 valence electrons
If we check the proper arrangement of Boron and Fluorine in the periodic table, we will find that the electronegativity value of boron is 2.04 and the electronegativity value of fluorine is 3.98. As per the rule, the atom with the least electronegative value should be at the structure’s center. Therefore, Fluorine is the outermost atom in the BF3 molecule, whereas boron is the center atom.
Valence electrons are the total number of electrons on an atom’s outermost shell. Only valence electrons contribute to the formation of chemical bonds.
Fluorine contains seven electrons on its outermost shell, hence it has seven valence electrons. Similarly, Boron has three valence electrons on its outermost shell, hence its valence electron count is three.
To complete their octet, all atoms require eight electrons in their valence shell (Exceptions: Boron, Beryllium, Aluminum, Hydrogen, Helium, and Lithium). The atoms form bonds with other atoms in the molecule to complete their octet. Bonding does not always include all of the electrons in the valence shell. Bonding electrons are those that participate in chemical bonding, whereas non-bonding or lone pair electrons are those that do not.Therefore, carbon will share its remaining three electrons with nitrogen to complete its octet, resulting in a triple bond between carbon and nitrogen.Boron contains three valence electrons and needs three extra electrons to be stable (as it only requires 6 electrons to become stable). Fluorine has 7 valence electrons and needs 1 more to complete its octet.
Boron, the central atom, shares three electrons with three fluorine atoms and forms three covalent bonds. The creation of three covalent bonds stabilizes the Boron and three Fluorine atoms.
BF3 Molecular Geometry
The BF3 molecule is trigonal planar. Boron trifluoride molecule is composed of three B – F bonds on the central atom Boron. This causes three zones of high electron density to form around the central Boron atom. The charge distribution is symmetrical around the central atom, and the three fluorine atoms are arranged in an equilateral triangle. The boron trifluoride molecule, therefore, has a trigonal planar structure.
- Boron trifluoride has a molar mass of 67.81 g/mol and a density of 2.76 kg/m3
- It reacts with moisture and gives off white fumes.
- It is a colorless, pungent gas with toxic properties.
- It is a volatile liquid at room temperature.
Hybridization is the process of combining atomic orbitals to form new hybrid orbitals.
For boron to bond with three fluorine atoms in boron trifluoride (BF3), the atomic s- and p-orbitals in boron’s outer shell mix to form three equivalent sp2 hybrid orbitals.
In the ground state, one boron electron is unpaired. The 2s orbital and two 2p orbitals hybridize during the formation of this molecule. As the lone pair, just one of the vacant p-orbitals remains. Boron requires three hybridized orbitals to create bonds with three F atoms, where the 2pz orbitals overlap with the hybridized sp2 orbitals, and bonds are produced.
Hence, the hybridization in the boron trifluoride (BF3) molecule is sp2.
Molar Mass of BF3
Molar mass of Boron = 10.81 g/molMolar mass of Fluorine = 19.00 g/mol
Molar mass of BF3 is 67.81 g/mol
BF3 is a nonpolar molecule.
To understand the non-polar nature of BF3, we need to understand its structure.
The Boron Trifluoride molecule has one Boron atom and three Fluorine atoms. Boron has a valency of 3 and Fluorine has a valency of 7. The fluorine atom, on the other hand, contains three lone pairs of electrons, therefore the molecular structure is a balanced and symmetric molecule.
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To summarize everything in this article, the following are some important points:
- In BF3 lewis structure, there are two different atoms: Boron, and Fluorine
- The bond angle is 120 degrees and there are 24 valence electrons in the molecule.
- BF3 is a nonpolar molecule with trigonal planar geometry.
- Exposure to Boron trifluoride can be dangerous.
Some of the frequently asked questions are given below
1. Why Boron trifluoride is polar?
BF3 is a non-polar compound. In BF3, the central boron atom has sp2 hybridized orbitals, resulting in an unfilled p orbital on the Bron atom and trigonal planar molecular geometry. Because the Boron-Fluorine bonds are all 120 degrees apart, any net dipole in that plane is canceled out. Even if each B-F bond is polar, the net dipole moment is zero because adding the bond vectors cancels everything out.
2. Why Lewis structures are important?
Lewis structure is a simplified representation of valence shell electrons.It depicts the arrangement of electrons around individual atoms in a molecule.
Electrons are shown as “dots” or as a line between two atoms when they are bonded.
3. How to draw Lewis structure of oxygen?
In the O2 Lewis structure, there is a double bond between two oxygen atoms.Oxygen is a diatomic nonpolar molecule with bond angles of 180 degrees.
In its molecule, both oxygen atoms have the same electronegativity value and both atoms share equal ratios of bonded shared electrons and the overall O2 molecule turns out to be nonpolar.
4. What is dot structure of Hydrogen Sulfide?
On both sides of the central sulfur atom in the H2S Lewis structure, there are two hydrogen atoms.The molecule bends due to the existence of two unbonded pairs of electrons.The molecule is slightly polar because sulfur is more electronegative than hydrogen.
In the case of H2S, the vectorial sum of the bond dipole moments results in a non-zero total dipole moment. As a result, dipole-dipole interactions are observed in hydrogen sulfide.
5. What is CLF3 molecular geometry?
ClF3 has a T-shaped molecular geometry and trigonal bipyramidal electron geometry. This molecule has two lone pairs and three bound pairs, according to the ClF3 Lewis structure. ClF3 is a polar compound.