Diborane is a colourless gas at room temperature with a repulsive, sweet odour. It adopts a D2h structure containing Four terminal and two bridging hydrogen atom
This molecule consists of 4 hydrogen atom and two boron atom. the boron atom is known to be sp3 Hybridized and has four hybrid orbitals
Three of the orbital from the four will have one electron each and one is with an empty orbital. The electron from each of the boron atom forms two bonds with the hydrogen atom.
Two bridge will form as a result of unpaired electron orbital and empty orbital of two atoms of boron. (B-H-B),this is also called a banana bond.
The bond between boron and terminal hydrogen are 2electron covalent bond.