Copper (II) Hydroxide

Brief Overview

Copper(II) hydroxide, also known as cupric oxide, is an inorganic compound and a weak base that appears as blue powder. Some manufacturers would claim they have "stabilized" copper(II) hydroxide, although they likely consist of a mixture of copper(II) carbonate and hydroxide. This is is thermodynamically unstable with respect to decomposition to the oxide. It is virtually insoluble in water and decomposes in hot water to the more stable copper(II) oxide and water. Copper(II) hydroxide dissolves quickly in mineral acids and ammonia solution. It is mildly amphoteric, and in concentrated alkali, it forms [Cu(OH)3]- or [Cu(OH)4]2- ions. Copper(II) hydroxides can be produced in a kinetically stabilized form depending on the method of precipitation and choice of additives

Manufacturing Process

Copper(II) hydroxide prepared by the addition of sodium hydroxide to a salt of copper decomposes at temperatures above 100°C, and in the presence of excess alkali, it decomposes at temperatures above 50°C. Copper(II) hydroxide is produced by a reaction of copper oxychloride in an aqueous suspension with alkali hydroxide or alkaline earth metal hydroxide in the presence of a stabilizing agent and the product is separated and washed.

                                                    Cu(NO₃)₂ + NaOH → Cu(OH)₂ + NaNO₃

Uses of Copper(II) Hydroxide in different industries:

• Copper(II) hydroxide in ammonia solution, known as Schweizer's reagent, can dissolve cellulose. Hence, it is used in the production of rayon, a cellulose fiber.

• Copper(II) hydroxide has been used as an alternative to the Bordeaux mixture, a fungicide and nematicide. It is also an ingredient in the manufacture of feed additives.

• Copper(II) hydroxide is also occasionally used as colorant in ceramic products.

• It is also used widely in the aquarium industry for its ability to destroy external parasites in fish, including flukes, marine ich, brook and marine velvet, without killing the fish.

• Copper(II) hydroxide has been combined with latex paint, making a product designed to control root growth in potted plants.