The molecular geometry of BF3 (boron trifluoride) is trigonal planar.

sp2 Hybridization: Boron Trifluoride

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F

F

close

Now that we have 3 uniform, singly occupied orbitals, we can bring in F to make Boron Trifluoride.

Hybridization State

BF3 bonds should all be equal, but remember that s bonds are stronger than p bonds, so nature has to do something to make the orbitals uniform. That something is hybridization.  

Promotion State

[He]

To create equal bond strength, we mix different orbitals and create one set of uniform hybrid orbitals.

Boron 5B [He] 2s22p1

[He] 2s22p1

As shown on the Periodic Table, Boron has a Ground State of [He] 2s22p1as represented by this orbital diagram.

5B

Ground State

Boron

sp2

p, 1

p, 2

s

3

1

To make BF3, we need 3 singly occupied orbitals to bond.

An electron is promoted to create three singly occupied orbitals for bonding.

2

Boron 5B [He] 2s22p1

Notice there is only one singly occupied orbital for bonding. Three are needed to make BF3. 

9F [He] 2s22p5

Fluorine

As shown on the Periodic Table, Fluorine has a Ground State of [He] 2s22p5 as represented by this orbital diagram.

Trigonal Planar

B

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BF3

sp2 in 3D

As shown on the Periodic Table, Fluorine has a Ground State of [He] 2s22p5 as represented by this orbital diagram.  

As shown on the Periodic Table, Boron has a Ground State of [He] 2s22p1 as represented by this orbital diagram.  

To make BF3, we need 3 singly occupied orbitals to bond.

BF3 bonds should all be equal, but remember that s bonds are stronger than p bonds, so nature has to do something to make the orbitals uniform. That something is hybridization.  

Now that we have 3 uniform, singly occupied orbitals, we can bring in F to make Boron Trifluoride.

Hybrid Orbital