Cadmium hydroxide is an inorganic compound

Inorganic compound

Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 with the formula Cd(OH)₂. It is a white crystalline ionic compound that is a key component of NiCd batteries.

Preparation and reactions

Cadmium hydroxide is produced by treating cadmium nitrate with sodium hydroxide:

Cd(NO₃)₂ + 2 NaOH → Cd(OH)₂ + 2 NaNO₃

Attempted preparation from other cadmium salts is more complicated. Cadmium hydroxide is more basic than zinc hydroxide

Zinc hydroxide

Zinc hydroxide Zn2 is an inorganic chemical compound. It also occurs naturally as 3 rare minerals: wülfingite , ashoverite and sweetite ....

. It forms the anionic complex Cd(OH)₄^2- when treated with concentrated caustic soda solution. It forms complexes with cyanide, thiocyanate and ammonium ions when added to the solutions of these ions. Cadmium hydroxide loses water on heating, producing cadmium oxide

Cadmium oxide

Cadmium oxide is an inorganic compound with the formula CdO. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide...

. Decomposition commences at 130 °C and is complete at 300 °C. Reactions with mineral acids (HX) produce the corresponding cadmium salts (CdX₂). With hydrochloric acid

Hydrochloric acid

Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

, sulfuric acid

Sulfuric acid

Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

 and nitric acid

Nitric acid

Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

, the products are cadmium chloride

Cadmium chloride

Cadmium chloride is a white crystalline compound of cadmium and chlorine, with the formula CdCl2. It is a hygroscopic solid that is highly soluble in water and slightly soluble in alcohol. Although it is considered to be ionic, it has considerable covalent character to its bonding...

, cadmium sulfate

Cadmium sulfate

Cadmium sulfate is the name of a series of related inorganic compounds with the formula CdSO4.xH2O. The most common form is the monohydrate CdSO4.H2O, but two other forms are known CdSO4.8/3H2O and the anhydrous salt...

 and cadmium nitrate

Cadmium nitrate

Cadmium nitrate describes any of a related members of a family of inorganic compound with the general formula Cd2.xH2O. The anhydrous form is volatile but the others are salts. All are colourless crystalline solids that absorb moisture from air and becomes watery, that is deliquescent...

, respectively.

Uses

It is generated in storage battery anodes, in nickel-cadmium and silver-cadmium storage batteries in its discharge:

Ni(OH)₂ + Cd → Cd(OH)₂ + Ni

The hydroxide is used in place of cadmium oxide

Cadmium oxide

Cadmium oxide is an inorganic compound with the formula CdO. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide...

for variety of operations.