Cadmium halides solution chemistry

The solution chemistry of zinc and cadmium halides is a topic of active interest, and numerous studies of the related equilibria shown in Scheme 3, in various solvents S, have been reported. 

X-ray diffraction, 929 Cadmium(I) complexes, 989 Cadmium halides, 981 molten state coordination, 981 solution chemistry, 893 Cadmium hydrides, 931 ammonia, 931... 

In its chemistry, cadmium exhibits exclusively the oxidation state 4- 2 in both ionic and covalent compounds. The hydroxide is soluble in acids to give cadmium(II) salts, and slightly soluble in concentrated alkali where hydroxocadmiates are probably formed it is therefore slightly amphoteric. It is also soluble in ammonia to give ammines, for example [Cd(NH3)4]2+. Of the halides, cadmium-(II) chloride is soluble in water, but besides [Cd(H20)J2+ ions, complex species [CdCl]+, [CdCl3] and the undissociated chloride [CdCl2] exist in the solution, and addition of chloride ion increases the concentrations of these chloro-complexes at the expense of Cd2+(aq) ions. 

Cadmium alkyls are useful reagents in organic chemistry for the conversion of acyl halides to ketones. They are prepared in situ by the direct addition of anhydrous CdCl2 to an ether solution of the Grignard reagent. 

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