Cadmium hydroxide is an inorganic compound with the formula Cd(OH)₂. It is a white crystalline ionic compound that is a key component of

nickel–cadmium battery The nickel–cadmium battery (Ni–Cd battery or NiCad battery) is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. The abbreviation ''Ni-Cd'' is derived from the chemical symbols of nickel (Ni) and ...

.Karl-Heinz Schulte-Schrepping, Magnus Piscator "Cadmium and Cadmium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH, Weinheim. .

Structure, preparation, and reactions

Cadmium hydroxide adopts the same structure as Mg(OH)₂, consisting of slabs of octahedral metal centers surrounded by octahedral of hydroxide ligands.Hemmingsen, L.; Bauer, R.; Bjerrum, M. J.; Schwarz, K.; Blaha, P.; Andersen, P., "Structure, Chemical Bonding, and Nuclear Quadrupole Interactions of β-Cd(OH)₂: Experiment and First Principles Calculations", Inorganic Chemistry 1999, volume 38, 2860-2867. It is produced by treating cadmium nitrate with sodium hydroxide: : Cd(NO₃)₂ + 2 NaOH → Cd(OH)₂ + 2 NaNO₃ Preparation has been achieved from some other cadmium salts, Cd(OH)₂ and

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 natura ...

react equivalently. Cadmium hydroxide is more basic than zinc hydroxide. It forms the anionic complex Cd(OH)₄²⁻ when treated with concentrated base. It forms complexes with cyanide, thiocyanate, and ammonia. Cadmium hydroxide loses water on heating, producing

. 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, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

, sulfuric acid, and

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

, the products are cadmium chloride,

cadmium sulfate Cadmium sulfate is the name of a series of related inorganic compounds with the formula CdSO4·H2O. The most common form is the monohydrate CdSO4·H2O, but two other forms are known CdSO4·H2O and the anhydrous salt (CdSO4). All salts are colourl ...

, and

cadmium nitrate Cadmium nitrate describes any of the related members of a family of inorganic compounds with the general formula Cd(NO3)2.\mathitH2O, the most commonly encountered form being the tetrahydrate. The anhydrous form is volatile, but the others are ...

, respectively.

Uses

It is generated in storage battery anodes, in nickel-cadmium and silver-cadmium storage batteries in its discharge: : 2 NiO(OH) + 2 H₂O + Cd → Cd(OH)₂ + Ni(OH)₂

References

{{Hydroxides Cadmium compounds Hydroxides