# Ethylenediamine Complexes of Nickel

## Hazards

• 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

## Materials

• four tall cylinders
• eyedropper
• glass stirring rods

Or

• pre-prepared display of the ethylenediamine complexes of nickel

## Procedure

1. Place 100 mL of the nickel (II) sulfate solution into each of the cylinders.
2. To one cylinder add a few drops (about 0.5 mLs) of the ethylenediamine solution to get the green-blue color of $$\ce{ Ni(H2O)4en2+ }$$
3. To the next cylinder add one or two mL of the ethylenediamine solution to get the blue color of $$\ce{Ni(H2O)2(en)22+ }$$
4. To the third cylinder add about 4 mL of the ethylenediamine solution to get the violet color of $$\ce{Ni(en)32+ }$$