Silver ionic radii

The higher ionisation energy and smaller ionic radius of copper contribute to its forming oxides much less polar, less stable, and less basic than those of the alkah metals (13). Because of the relative instabiUty of its oxides, copper joins silver in occurring in nature in the metallic state. 

The ionophoric properties of 13 toward soft metal cations were evaluated by using the picrate extraction method. Metal ions like Ag" (91%), Tl" (38%) and Hg " (16%) were extracted efficiently with a maximum for Ag". Cu ", Co ", Zn ", Cd ", and ions were not extracted. The better ex-tractability of 13 toward silver(I) cation was attributed to the latter s high affinity for sulfur. A fast exchange process, on the NMR time scale, was observed by NMR between free and complexed 13. In presence of a twofold excess of Ag(I) salt, a 2 4 complex 132 (AgPic)4 was formed (see below) [70]. With this type of complex, the ionic radius of the metal ion is not concerned and the softness of the metal ion should be considered relatively to the soft... 

Silver. The common oxidation state is Ag, which has an ionic radius between Na and and nearer to the former. Rather gratifyingly, the ratio Ag/Na is quite constant between peridotites (BVSP), MORE and other basalts (Laul et al, 1972 Hertogen et al., 1980), and continental crust (Gao et al., 1998) at (1.6 1.0) X 10 , giving 4 ppb in the PM. Silver reported by Garuti et al. (1984) in massive peridotites of the Ivrea zone is much higher and does not appear realistic. 

The SH groups of cysteine residues (177) in the rabbit liver protein metallothionein (MT) and two of its fractions (a-MT, /S-MT) can bind transition metal ions. Thus, formation of the silver complexes Agi2-MT, Agis-MT, Ag6-a-MT and Ag6-/S-MT was determined by circular dichroism (CD), when zinc complexes of metallothionein and its fractions were titrated with Ag(I) ions. The intense CD spectrum of one of the silver complexes was attributed to supercoil formation245. The UVV spectra of bilirubin (168) and its complexes with Cu(II), Ag(I) and Au(III) showed that the complexes had different structures, due to differences of ionic charge and ionic radius between the metal ions238. 

Yttrium is trivalent and has an effective ionic radius of 0.900 angstroms. At room temperature the metal structure is hexagonal, close packed, and diamagnetic. The metal yttrium has a silver-metallic luster and is relatively stable in air. 

Figure 4. Activation energy (kcal mole 1) of the DC conduction vs. the ionic radius, obtained with pressed silver electrodes (X) or with platinum electrodes (O and O)...

Ethanol has also received considerable attention as a solvent over a long period of time. Data on this solvent, however, are rather few compared to methanol and very few systematic studies exist. Several solubility studies have been made since the publication of Seidell and Linke. Thomas has reported solubilities for the alkali metal iodides at 20 and 25°C, and observed a decrease in solubility with an increase in ionic radius of the cation. Deno and Berkheimer have reported the solubilities of several tetraalkylammonium perchlorates. In every case the solid phase was the pure salt. Solubilities for several rare earth compounds have been reported.Since all of these salts form solvates in the solid phase, the results cannot be used in thermodynamic calculations without the corresponding thermodynamic values for the solid phases. Solubilities of silver chloride, caesium chloride, silver benzoate, silver salicylate and caesium nitrate have been measured in ethanol, using radioactive tracer techniques. Burgaud has measured the solubility of LiCl from 10.2 to 57.6°C and observed that there is a transition from the four-solvated solid phase to the non-solvated phase at 20.4°C. 

Only silver(I) is stable in aqueous solutions. The solubility of silver oxide, Ag20, in both crystalline and amorphous forms has been studied. Hydrolysis species that form are only monomeric. Two species have been postulated, AgOH(aq) and Ag(OH)2, consistent with the two-coordinate nature of silver(I). The ionic radius of silver(I) reported by Shannon (1976) is 0.67 A. 

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