Question

Describe the shapes of $BF_{3}$ and $[BH_{4}]^{-}$. Assign the hybridisation of boron in these species.

Answer 1

i) $B{ F }_{ 3 }:$

Boron tends to produce monomeric covalent halides due to its “small size” and “high electronegativity”. These halides have a triangular planar geometry. This triangular shape consists of the overlap between three ${ sp }^{ 2 }$ hybridized boron orbitals and the sp orbitals of three halogen atoms. Boron have ${ sp }^{ 2 }$ hybridization.

(ii) ${ BH }_{ 4 }^{ - }:$

The hybridization of boron-hydride ion is ${ sp }^{ 3 }$ and geometry of ${ BH }_{ 4 }^{ - }$ is tetrahedral.

Answer 2

) B{ F }_{ 3 }:BF3​:

Boron tends to produce monomeric covalent halides due to its “small size” and “high electronegativity”. These halides have a triangular planar geometry. This triangular shape consists of the overlap between three { sp }^{ 2 }sp2 hybridized boron orbitals and the sp orbitals of three halogen atoms. Boron have { sp }^{ 2 }sp2 hybridization.

(ii) { BH }_{ 4 }^{ - }:BH4−​:

The hybridization of boron-hydrid