Question

The simplest boron hydride is diborane. 

1. Write down the molecular formula of diborane. 

2. Distinguish between terminal hydrogen and bridging hydrogen atoms of diboran.

Answer 1

1. B₂H₆ 

2. In diborane, four hydrogen atoms and two boron atoms are present in a single plane. These hydrogen atoms are called terminal atoms. The terminal B-H bonds are regular two centre-two electron bonds. The remaining two hydrogen atoms above and below this plane are called bridging hydrogen atoms. The two bridge bonds (BH-B) are three centre-two electron bonds