Which one of the following elements is unable to form MF₆^3– ion?

Match the interhalogen compounds of column-I with the geometry in column-II and assign the correct code.

Column $${\rm I}$$			Column $${\rm I}$$$${\rm I}$$
(A)	XX'		(i)	T-shape
(B)	XX'3		(ii)	Pentagonal bipyramidal
(C)	XX'5		(iii)	Linear
(D)	XX'7		(iv)	Square pyramidal
			(v)	Tetrahedral

In which pair of ions both the species contain S $$-$$ S bond?

It is because of inability of ns² electrons of the valence shell to participate in bonding that