Question

what are the symmetry species of the vibrations of SF6 that are both IR and Raman active?

Answer 1

SF₆ belongs to the octahedral point group.

We can find out the symmetry species which are Raman and IR active .

By looking at the character table we find out that the none of the vibration modes is both Raman and IR active .

The Representation which transforms like the x,y,z coordinates are IR active while the double products are Raman active .
By looking at the table we find out that T_1u stretching band is IR active while A_1g and E_g modes are Raman active.