Nickel ion complexes. Three beakers with nickel ion complexes. When nickel(II) chloride (NiCl2) is dissolved in water, it forms a green nickel aquo complex ((Ni(H2O)6)2+, 0.2M concentration, front beaker). When ammonia (NH4OH) is added to the solution, at first pale blue nickel hydroxide (Ni(OH)2) is formed, but it quickly dissolves in excess ammonia to form a blue solution of hexaamminenickel(II) complex ((Ni(NH3)6)2+, middle beaker). When ethylenediamine (C2H4(NH2)2, en) is added to the solution, it forms a violet solution of tris(ethylenediamine)nickel(II) complex ((Ni(en)3)2+, back beaker). |