The Group IIB metals

Electrochemical oxidation of the group-IIB metal can generate metal-metal bonds analogously to the manner described in 8.3.3.4. For example, cyclic voltammetry with Hg electrodes shows that M(CO)2dpam (M = Cr, Mo) reacts to form Hg—M bonds in two stages ... 

The extraction of the Group IIB metals from aqueous solution is of obvious commercial importance and continues to be investigated.996-1000 The precise species which is extracted depends on the pH, but both Aliquat 336 and tri-n-butyl phosphate extract [ZnCl3]- from LiQ solution and [ZnCl4]2- from acidic media. 

Wet Tests.— When hydrogen sulphide is passed through an acidified solution containing molybdenum, the trisulphide is thrown dowm. The precipitate dissolves in ammonium sulphide, and it is therefore in ordinary analysis separated with the Group IIb metals, namely, arsenic, antimony, tin, gold, and platinum. The last four metals may be precipitated by addition of metallic zinc, the arsenic expelled by evaporation, and, after taking to dryness with nitric acid, the molybdenum may be extracted from the residue with ammonia. The trisulphide may be reprecipitated directly by the addition of nitric acid to the solution in ammonium sulphide. A soluble sulphide added to a solution of ammonium molybdate gives a blue colour. 

The group-IIB metal dihalide is added to the solution of the transmetallating reagent either in small portions or in solution. The solubility of Hg(II) halides is not considerable, even in ether, and if solid HgXj is added, vigorous stirring is advisable. 

The group IIB metals are also capable of inserting into the metal-metal bond of a number of transition metal carbonyl complexes. The reaction procedure normally involves stirring a solution of the metal-metal-bonded complex with powdered Zn or Cd... 

Table lists the insertion products of the group IIB metals. 

The complexation of the Group IIB metals by amino-acid and related derivatives continues to be a subject of interest stability constants reported include those for histidine and its derivatives, histamine, glycylhistamine, aspartic and glutamic acids, aspargine, glutamine, glycine, cysteine, and alanine. " ... 

The Group IIB metal soap (Cd or Zn) is the primary stabilizer. It replaces an unstable Cl atom by a stable ester group,... 

Some of the results obtained on the group IIB metals by the level-crossing, optical double-resonance, and optical pumping techniques are given in Table 18.6. The level-... 

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