Explain the structure of diborane ?

I) Structure of diborane
i) Diborane is an electron deficient molecule. It contains 12 electrons and short of 2 electrons or the formation of covalent bond.
ii) Electron diffraction studies have shown that diborane contains two co-planar BH₂ groups. And has two types of hydrogen atoms.
i) Four terminal H-atoms (H_t)
ii) Two Bridge H-atoms (H_b)

II) Orbital structure of diborane
i) In B2H6 each boran atom undergoes sp³ hybridisation.
ii) out of the four hybrid orbitals of boran atom, three orbitals have one electron each and fourth orbital is vacant.
iii) In forming B –H – B Bridge, sp3 hybrid orbital with one electron from one boran atom, 1sorbital of one bridge hydrogen and the vacant sp³ hybrid orbital of the second boran atom
overlaps as shown in the figure.

iv) The B-H-B bridges present in Diborane are abnormal bonds.
v) They are considered as three centered two electron bonds. This type of bond is called banana bond or tau bond. In this type of bond pair of electrons hold three atoms.