Summary
Ammine complexes of 2+ ions of copper, nickel and cobalt are made by the addition of ammonium hydroxide. The distinct color of the different metal ammines are observed.
Hazards
- Conc. ammonium hydroxide is toxic and corrosive. Avoid exposure.
- Nickel salts are considered possible carcinogens. Use care.
Chemicals and Solutions
- Conc. Ammonium hydroxide
- 0.1M Copper sulfate
- 0.1M Nickel nitrate
- 0.1M Cobalt chloride
Materials
- 3 hydrometer cylinders
- 3 stir rods
Procedure
Add approximately 2 parts of ammonium hydroxide to each of the metal ion solutions to generate the ammine.
Discussion
\( \ce{ $\underset{\text{super blue}}{\ce{ Cu^2+_{(aq)} + 4NH3_{(aq)} -> Cu(NH3)4^2+_{(aq)} }}$ } \)
\( \ce{ $\underset{\text{violet}}{\ce{ Ni^2+_{(aq)} + 6NH3_{(aq)} -> Ni(NH3)6^2+_{(aq)} }}$ } \)
\( \ce{ $\underset{\text{red/orange}}{\ce{ Co^2+_{(aq)} + 6NH3_{(aq)} -> Co(NH3)6^2+_{(aq)} }}$ } \)