Chem Bond

The hybridisation in SO₂ is sp² with a bent structure because of a lone pair occupying one sp² orbital.

Now, the surprising part about IBr₂^- is that though it has linear shape it has a hybridisation of sp³d. Can you think why?

Try drawing the structure of both the compounds keeping in mind the lone pairs (One in SO₂ and 2 lone pairs in IBr₂^-)