Cadmium hydroxide

Cadmiumdihydroxid

White solid

Fixed

4.79 g · cm -1

300 ° C.

Insoluble in water

Attention

Repealed as carcinogenic

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Cadmium hydroxide is a chemical compound of cadmium from the group of the hydroxides. It is a solid, white substance which decomposes at about 300 ° C.

Production and representation

Cadmium hydroxide is produced by reaction of bases with cadmium salt solutions and precipitation. Finely crystalline cadmium can only be obtained by the reaction of cadmium nitrate solution with sodium hydroxide.

High concentrations of halide ions prevent the formation of cadmium hydroxide, as the [ CDX4 ] 2 - ion ( X = F, Cl, Br, I) forms.

Properties

Cadmium hydroxide crystallizes in the hexagonal crystal system with space group with lattice parameters a = 349.9 pm and c = 470.1 pm and one formula unit per unit cell. The structure thus corresponds to the brucite structure and is closely related to the Cadmiumiodidstruktur.

Cadmium hydroxide as compared to more basic zinc hydroxide and therefore dissolves only in strong bases. Ammonia is to form hexammine ions [Cd (NH3) 6] 2 is soluble.

Use

Cadmium hydroxide is used as an anode material discharged nickel-cadmium batteries. In the anode manufacturing, it is produced by oxidation of metallic cadmium due to hydrogen peroxide on the support material. Also, it occurs during the discharge process, these accumulators, loading it is reduced to cadmium.

For the recovery of other cadmium compounds it replaced more frequently cadmium.