BH3 Lewis structure

BH₃ (borane) has one boron atom and three hydrogen atoms.

In the BH₃ Lewis structure, there are three single bonds around the boron atom, with three hydrogen atoms attached to it, and none of the atoms has a lone pair.

Alternative method: Lewis structure of BH₃

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, boron lies in group 13, and hydrogen lies in group 1.

Hence, boron has three valence electrons and hydrogen has one valence electron.

Since BH₃ has one boron atom and three hydrogen atoms, so…

Valence electrons of one boron atom = 3 × 1 = 3
Valence electrons of three hydrogen atoms = 1 × 3 = 3

And the total valence electrons = 3 + 3 = 6

Learn how to find: Boron valence electrons and Hydrogen valence electrons

• Second, find the total electron pairs

We have a total of 6 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 6 ÷ 2 = 3

• Third, determine the central atom

Here hydrogen can not be the central atom. Because the central atom is bonded with at least two other atoms, and hydrogen has only one electron in its last shell, so it can not make more than one bond.

Hence, here we have to assume that the central atom is boron.

Therefore, place boron in the center and hydrogens on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 3 electron pairs. And three B — H bonds are already marked. So we do not have to mark any electron pair as a lone pair on the sketch.

Final structure

The final structure of BH₃ consists of a central boron atom connected to three hydrogen atoms through single covalent bonds. In this configuration, the boron atom is an exception to the octet rule, as it is stable with only six valence electrons in its outer shell. Within this layout, each of the three hydrogen atoms achieves its stable duet state through its respective single bond. This arrangement represents the most stable state for the molecule because it results in a formal charge of zero for every atom involved. Consequently, this specific electronic distribution serves as the definitive and most accurate Lewis representation of borane.

Next: C₂H₆ Lewis structure

External video

• BH3 Lewis Structure – How to Draw the Lewis Structure for BH3 – YouTube • Wayne Breslyn

External links

• https://www.chemistryscl.com/general/BH3-lewis-structure/
• https://lambdageeks.com/bh3-lewis-structure/
• https://topblogtenz.com/bh3-lewis-structure-molecular-geometry-bond-angle-hybridization/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/BH3-lewis-structure.html
• https://socratic.org/questions/what-is-the-lewis-dot-structure-of-bh-3-how-many-lone-pair-electrons-are-in-this