Multiple choice The pair of ion that forms complex with coordination number 2 is Cd(II) and Hg(II) Cu(II) and Hg(II) Cd(II) and Hg(I) Cu(I) and Hg(II) None of these Reveal answer Fill a bubble to check yourself D Correct answer Explanation This option is correct, because the Cu(I) and Hg(II) metals ions act as the minimum repulsion in between ligand to formed linear geometry of the complex.