BF3 (Boron trifluoride) Lewis Structure (2024)

Let’s explore the Lewis structure of boron trifluoride, BF3.

The BF3 molecule comprises a central boron (B) atom and three surrounding fluorine (F) atoms. Boron resides in group 13 of the periodic table, boasting three valence electrons, while each fluorine atom originates from group 17, contributing seven valence electrons.

Step-by-Step Guide to Drawing the Lewis Structure of BF3

1. Calculating the Total Valence Electrons

A prerequisite for accurately portraying the BF3 Lewis structure is determining the cumulative valence electrons. Sum the valence electrons of each atom:

• Valence electrons in boron (B): 3 electrons
• Valence electrons in fluorine (F): 7 electrons x 3 atoms = 21 electrons

Total valence electrons = 3 + 21 = 24 electrons

2. Identify the Central Atom

In BF3, boron (B) is the central atom, as it is less electronegative than fluorine and can only form single bonds.

3. Laying the Foundation with an Initial Skeleton

Position the boron atom (B) at the center and surround it with the three fluorine atoms (F), forming single bonds between boron and each fluorine atom. This initial arrangement establishes a balanced foundation.

4. Distributing Excess Valence Electrons

With the preliminary structure in place, proceed to allocate the remaining valence electrons to fulfill the octet rule for each atom. Fluorine atoms, striving for an octet, will each obtain a single lone pair of electrons. Boron, however, can accommodate fewer than eight electrons due to its electron-deficient nature.

5. Check Octet Rule and Adjust

At this step, you need to check the stability of the outer atoms.

In the drawing of the BF3 molecule, you can see the atoms on the outside are fluorine atoms.

All the fluorine atoms have full octets and are in a stable state.

In the first step, we figured out how many electrons are in the BF3 molecule.

The whole BF3 molecule has 24 electrons in total, and we used up all these electrons in the drawing we did earlier.

So, there aren’t any extra pairs of electrons left to put on the center atom.

6. Check Formal Charges

Evaluate formal charges to determine the most plausible Lewis structure. Employ the formal charge formula:

FC (Formal charge) = V (Number of valence electrons) – N (Number of nonbonding valence electrons) – B (total number of electrons shared in bonds)/2.

For Boron atom: V = 3, B = 6, N = 0

FC = 3 – 0 – 6/2 = 0

For Fluorine atom: V = 7, B = 2, N = 6

FC = 7 – 6 – 2/2 = 0

Refine the electron distribution to minimize formal charges, aiming for a configuration with the most stable and balanced charge arrangement.

7. Finalizing the Lewis Structure

The final Lewis structure for BF3 should look like this:

FAQ

1. What is the Lewis structure of BF3?

The Lewis structure of BF3 represents the arrangement of atoms and valence electrons in a boron trifluoride molecule.

2. How many valence electrons does boron (B) have in BF3?

Boron (B) has 3 valence electrons in the BF3 molecule.

3. How many valence electrons does fluorine (F) have in BF3?

Each fluorine (F) atom has 7 valence electrons in the BF3 molecule.

4. What is the total number of valence electrons in the BF3 molecule?

The total number of valence electrons in BF3 is 24 (3 from boron and 7 from each of the three fluorine atoms).

5. What is the molecular geometry of BF3?

BF3 has a trigonal planar molecular geometry, where the central boron atom is surrounded by three fluorine atoms.

6. How many lone pairs are on the central boron (B) atom in BF3?

The central boron (B) atom in BF3 does not have any lone pairs of electrons.

7. What is the bond angle in BF3?

The bond angle in BF3 is approximately 120 degrees between the boron-fluorine-boron atoms.

8. Is BF3 a polar molecule?

BF3 is a nonpolar molecule due to its symmetrical trigonal planar geometry, which cancels out the individual dipole moments of the boron-fluorine bonds.

9. What is the hybridization of the central boron (B) atom in BF3?

The central boron (B) atom in BF3 undergoes sp2 hybridization, forming three hybrid orbitals for bonding.

10. Can you describe any resonance structures of BF3?

BF3 does not exhibit resonance structures since there are no multiple bond placements or delocalized electrons within the molecule. The Lewis structure accurately represents its bonding arrangement.