cuprammonio

Cuprammonio refers to a complex ion containing copper and ammonia. The most common form is the tetraamminecopper(II) ion, [Cu(NH3)4(H2O)2]2+ or [Cu(NH3)4]2+, which appears as a deep blue solution. This complex is formed when copper(II) ions react with ammonia. It plays a significant role in analytical chemistry, particularly in the detection and separation of copper.

The formation of the cuprammonio complex is a reversible reaction. When copper(II) hydroxide, a precipitate formed by adding a base to a copper(II) solution, is treated with aqueous ammonia, it dissolves to form the characteristic deep blue solution of the tetraamminecopper(II) ion. This reaction is often used as a qualitative test for copper ions. The complex is relatively stable in alkaline solutions but dissociates in acidic solutions, reforming the copper(II) ion and releasing ammonia.

Beyond analytical applications, cuprammonio complexes are sometimes used in the textile industry as solvents for cellulose, enabling the regeneration of cellulose into fibers like rayon. The ability of the ammonia molecules to coordinate with the copper ion and disrupt the hydrogen bonding within the cellulose structure makes it an effective solvent. The toxicity and environmental impact of copper and ammonia also need to be considered in industrial applications.