Question

For $B{F}_3$ molecule, which of the following is/are true?

• A. B-atom is $s{p}^2$ hybridised.
• B. There is a $p\pi -p\pi$ back bonding in this molecule.
• C. Observed B-F bond length is found to be less than the expected bond length.
• D. There is a $p\pi -d\pi$ back bonding in this molecule.

Answer 1

Answer: (A), (B), (C)

B-atom is $s{p}^2$ hybridised.
Observed B-F bond length is found to be less than the expected bond length.
There is a $p\pi -p\pi$ back bonding in this molecule.

$B{F}_3$ is $s{p}^2$ hybridized with $3$ bond pairs and zeo lone pairs. Decrease in $B-F$ bond length is due to delocalised $p\pi -p\pi$ bonding between filled p-orbital of F atom and vacant p-orbital of $B$ atom. $p\pi -d\pi$ back bonding is not possible in this molecule because of absence of d-orbitals in $B$ and $F$.