Name: Properties of Boron and Its Uses
Uploaded: 2019-07-19
Duration: 5 min 42 s
Description: Boron is used in producing cleaning products such as detergent bleaches, glasses, ceramics etc. Let’s learn more about the uses of boron and its compounds th...

Question

Explain the structures of diborane and boric acid.

Accepted Answer

Diborane
$B_{2} H_{6}$ is an electron-deficient compound. $B_{2} H_{6}$ has only 12 electrons – Six electrons from six $H$ atoms and three electrons each from two $B$ atoms. Thus, after combining with three $H$ atoms, none of the boron atoms has any electrons left. X-ray diffraction studies have shown the structure of diborane as:

The four terminal hydrogen atoms and the two boron atoms lie in one plane. Above and below this plane, there are two bridging hydrogen atoms. The four terminal $B - H$ bonds are regular two-centre two-electron bonds while the two bridge $(B - H - B)$ bonds are
different and can be described in terms of three-centre two-electron bonds.

Boric acid has a layered structure. Each planar ${BO}_{3}$ unit is linked to one another through $H$ atoms. The $H$ atoms form a covalent bond with a ${BO}_{3}$ unit, while a hydrogen bond is formed with another ${BO}_{3}$ unit.

In the above-given figure, the dotted lines represent hydrogen bonds.

Explain the structures of diborane and boric acid.

Important Questions on The p-Block Elements

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