Nickel sulfate is considered a cancer suspect agent.
Ethylenediamine in ethanol is flammable and corrosive.
Chemicals and Solutions:
400 mL 0.lM nickel (II) sulfate
10 mL 25% ethylenediamine solution in ethanol
Four tall cylinders
glass stirring rods
OR: pre-prepared display of the ethylenediamine complexes of nickel
Place 100 mL of the nickel (II) sulfate solution into each of the cylinders. To one cylinder add a few drops (about 0.5 mLs) of the ethylenediamine solution to get the green-blue color of Ni(H2O)4en2+. To the next cylinder add one or two mL of the ethylenediamine solution to get the blue color of Ni(H2O)2(en)22+. To the third cylinder add about 4 mL of the ethylenediamine solution to get the violet color of Ni(en)32+.