Anionic interactions cadmium

Metal carboxyiates have been considered as nucleophilic agents capable of removing aHyUc chlorine and thereby affording stabilization (143). Typical PVC stabilizers, eg, tin, lead, or cadmium esters, actually promote the degradation of VDC polymers. The metal cations in these compounds are much too acidic to be used with VDC polymers. An effective carboxylate stabilizer must contain a metal cation sufftcientiy acidic to interact with aHyUc chlorine and to facihtate its displacement by the carboxylate anion, but at the same time not acidic enough to strip chlorine from the polymer main chain (144). 

The cadmium electrodeposition on the cadmium electrode from water-ethanol [222, 223], water-DMSO [224], and water-acetonitrile mixtures [225-229] was studied intensively. It was found that promotion of Cd(II) electrodeposition [222] was caused by the formation of unstable solvates of Cd(II) ions with adsorbed alcohol molecules or by interaction with adsorbed perchlorate anions. In the presence of 1 anions, the formation of activated Cd(II)-I complex in adsorbed layer accelerated the electrode reaction [223]. 

An EMF method has been used to study the interaction of ZnCl2 with chloride ion in methanol. It is found that Kx (7.76 x 103 M) is less than K2 (1.74 x 104 M), a finding which is interpreted in terms of passing from an octahedral [ZnCl(MeOH)5]+ species to a tetrahedral [ZnCl2(MeOH)2] complex.967 Related studies have shown that the solubility of cadmium halides in water decreases with increasing pressure.968 969 Anionic [ZnCl3] and [ZnCU]2-species are present in zinc chloride battery electrolyte, and are responsible for the observed negative transference numbers for zinc in aqueous acidic chloride medium.970 In neutral... 

Raman spectral studies of the species MX(n" 2) (n = 2—4 M = Zn, Cd, or Hg X = Cl, Br, or I) in anhydrous tributyl phosphate have been reported.24 For the MX2 molecules, sufficient metal dihalide-solvent interaction exists to suggest bent X—M—X species with C2v rather than >ooh symmetry. The effect appears most marked for zinc(n) and least marked for mercury(n), which is in accord with the Lewis acidity sequence ZnX2 > CdX2 > HgX2. A similar analysis of the anionic MX3 complexes formed from a 1 1 mixture of LiX and MX2 again demonstrates solvent interaction, and a tetrahedral C3v species is indicated, rather than the planar structure found in the solid state. Studies involving the halogeno-complexes of zinc, cadmium, and mercury in DMSO and DMF have also been reported.25,26... 

Natan M. J., Thackeray J. W. and Wrighton M. S. (1986), Interaction of thiols with n-type cadmium sulfide and n-type cadmium selenide in aqueous solutions adsorption of thiolate anion and efficient photoelectrochemical oxidation to disulfides , J. Phys. Chem. 90, 4089-4098. 

CAM] Caminiti, R., Nickel and cadmium phosphates in aqueous solution. Cation-anion complex formation and phosphate - H2O interactions, J. Chem. Phys., 77, (1982), 5682-5686. Cited on page 205. 

M. J. Natan, J. W. Thackeray, M. S. Wrigh-ton. Interaction of Thiols with n-Type Cadmium Sulfide and n-Type Cadmimn Selenide in Aqueous Solutions Adsorption of Thiolate Anion and Efficient Photoelectrochemical Oxidation to Disulfides, . Phys. Chem. 1986, 90,4089-4098. 

In addition to the adsorption studies of carbonyl, phosphine oxide, and sulfide adsorbates noted in Ref. 10, the studies of interaction of anionic S donors such as dithiocarbamates [17], anionic S-containing species (MoS and Et2NCS ) [18], thiolates [19], and polysulfides [20] with cadmium chalcogenides have been characterized by Wrighton and coworkers [17-20]. This chapter will focus on surface modification of cadmium chalcogenides with thiols, dithiols, sulfides, and disulfides. 

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