Pcl5 exist but bicl5 not exist why
Hi Sudhir,
I would like to answer your question. See what happens is when we go down the group there is a phenomenon that comes under play which is inert pair effect. According to which as we go down the group the size of the atom increases and as a result stability of +5 oxidation state is reduced and +3 oxidation state id dominant and thus BiCl5 doesn't exist.
Good Luck !!