Original sentence: Just as the elements in groups 3 through 7 form compounds analogous to those formed by elements in groups 13 through 17 (such as  and ,  and ,  and , etc.Tetrahedral structures are seen for the electronically related oxides  and
Edited sentence: Just as the elements in groups 3 through 7 form compounds analogous to those formed by elements in groups 13 through 17 (e.Tetrahedral structures are seen for the electronically related oxides MnO4− and CrO42−.TiCl4 and GeCl4, VF5 and AsF5, CrO42- and SeO42-, etc