Question

In the structure of diborane:

• A. all hydrogen atoms lie in one plane and boron atoms lie in a plane perpendicular to this plane.
• B. 2 boron atoms and 4 terminal hydrogen atoms lie in the same plane and 2 bridging hydrogen atoms lie in the perpendicular plane.
• C. 4 bridging hydrogen atoms and boron atoms lie in one plane and two terminal hydrogen atoms lie in a plane perpendicular to this plane.
• D. all the atoms are in the same plane.

Answer 1

The correct option is B 2 boron atoms and 4 terminal hydrogen atoms lie in the same plane and 2 bridging hydrogen atoms lie in the perpendicular plane.

In the structure of the Diborane, the four-terminal hydrogen atoms and the two boron atoms are lying in one plane. Above and below this plane, there are two H atoms bridge.

The four-terminal B-H bonds are regular two centre-two electron bonds. But the two bridge bonds are different and can be described as three center -two-electron bonds.

Diborane is the electron-deficient molecule and it does not have enough valence electrons to form a separate two-electron bond between each pair of the bonded atoms.

Thus option B is correct.