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Ammines

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

\( \ce{ $\underset{\text{super blue}}{\ce{ Cu^2+_{(aq)} + 4NH3_{(aq)} -> Cu(NH3)4^2+_{(aq)} }}$ } \)

\( \ce{ $\underset{\text{violet}}{\ce{ Ni^2+_{(aq)} + 6NH3_{(aq)} -> Ni(NH3)6^2+_{(aq)} }}$ } \)

\( \ce{ $\underset{\text{red/orange}}{\ce{ Co^2+_{(aq)} + 6NH3_{(aq)} -> Co(NH3)6^2+_{(aq)} }}$ } \)

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