Schweizer's reagent

Schweizer's reagent is a deep-blue solution of the coordination complex tetraammine copper(II) hydroxide. This solution can be produced by dissolving copper(II) hydroxide in an excess of ammonia. It is notable for its ability to dissolve cellulose, and a solution of cellulose in Schweizer's reagent can be used to manufacture rayon fiber by injecting it into sulfuric acid solution.