Schweizer's reagent

model]] of the tetraamminediaquacopper (II) cation, [Cu(NH3)4(H2O)2]2+]] Schweizer's reagent is the chemical complex tetraamminediaquacopper dihydroxide, [Cu(NH3)4(H2O)2](OH)2. It is prepared by precipitating copper(II) hydroxide from an aqueous solution of copper sulphate using sodium hydroxide or ammonia, then dissolving the precipitate in a solution of ammonia.

When the entire amount of copper is precipitated as hydroxide, it is advisable to filter it and dispose of the filtrate and rinse the precipitate from sulfate and other excess ions.

Water solution of tetraamminecopper(II) hydroxide.

It forms a deep azure solution. If the solution is evaporated, it leaves light blue precipitate of copper hydroxide. This is because the formation of the tetraminocupric complex is reversible and ammonia evaporates together with the water. If the evaporation is conducted under stream of ammonia, then deep blue needle-like crystals are formed. These crystals should be kept in isolation or in ammonia atmosphere. Besides, when the concentration of ammonia solutions is very high, divalent copper ions in presence of dioxygen, catalyze ammonia oxidation, giving rise to copper ammine nitrites: Cu(NO2)2(NH3)n;<ref>{{cite journal|first= Y.|last= Cudennec|title = Étude cinétique de l'oxydation de l'ammoniac en présence d'ions cuivriques|trans-title=Kinetic study of the oxidation of ammonia in the presence of cupric ions|journal = Comptes Rendus de l'Académie des Sciences, Série IIB|volume = 320 | issue = 6 |pages = 309–316|year =

See also
  • Tetramminecopper(II) sulfate

Footnotes

    References
    • Walther Burchard; Norbert Habermann; Peter Klüfers; Bernd Seger; Ulf Wilhelm (1994). "Cellulose in Schweizer's Reagent: A Stable, Polymeric Metal Complex with High Chain Stiffness". Angewandte Chemie International Edition in English. 33 (8): 884–887. doi:10.1002/anie.199408841.
    • Eduard Schweizer (1857). "Das Kupferoxyd-Ammoniak, ein Auflösungsmittel für die Pflanzenfaser" [Copper ammonium oxide, a solvent for plant fibers]. Journal für praktische Chemie. 72 (1): 109–111. doi:10.1002/prac.18570720115.
    • George B Kauffman (1984). "Eduard Schweizer (1818-1860): The Unknown Chemist and His Well-Known Reagent". J. Chem. Educ. 61 (12): 1095–1097. doi:10.1021/ed061p1095.
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