The process of mixing of one s- orbital ,three p- orbitals and two d-orbital in an atom to form six sp3 d2 hybrid orbitals of equivalent energy is called sp3 d2 hybridization.
EXAMPLE – SULPHUR HEXACHLORIDE (SF6)
In the last post we studied the hybridization in SF4 molecule. The central sulphur atom was sp3d hybridized. It had a lone pair of electrons. However, under different reaction conditions, sulphur atom can excite the electron in the 3p orbital (one of the lone pair of electrons) to vacant d- orbital to form six unpaired electrons. Then the 3s, 3p and 3d orbitals hybridize to form six sp3 d2 hybrid orbitals of equivalent energy. Later the molecule is formed with six fluorine atoms.
This is one of the coolest gas ! It is called a DEEP VOICE GAS.Inhaling the gas results in the person’s voice getting deeper . This happens because SF6 gas is about 5 times heavier than air.
As it has six electron pairs surrounding the central atom , it has an octahedral symmetry as predicted by VSEPR.The fluorine atoms are directed towards six corners of a regular octahedron as shown below-
The molecule has octahedral geometry with bond angle 90º.
Some other ions which exhibit this hybridization are PF6– , SiF6— , AlF6— .
We shall continue our discussion on hybridization in the next post as well. Till then,
Be a perpetual student of life and keep learning…
Good day !