Multiple choice Which of the following is non-ionisable? [CO (NH3)6] Cl3 [CO (NH3)3 Cl3] [CO (NH3)4 Cl2] Cl [CO (NH3)5 Cl] Cl2 Reveal answer Fill a bubble to check yourself B Correct answer Explanation A complex is non-ionisable if there are no counter-ions outside the coordination sphere. In [CO(NH3)3Cl3], all ligands are inside the coordination sphere, so it does not ionize in water.