Gold III Halide Solutions

The coordination numbers can be less precisely determined primarily because of the correlation between the frequency, n, and the rms variation, l. An increase in the value of n and a decrease in l will have similar effects and will both increase the calculated intensity values in the 

Results from Least-Squares Refinements of X-ray Diffraction Data for Gold(III) Halide Solutions 

Alternatively, the structural parameters for the complexes can be determined in r space by fitting calculated peaks for different d, l, and n values to observed peaks in the RDFs. Since the background curve, which is determined by the remaining structure in the solution, is not known, this method also leads to uncertainties in the determination of l and n values, especially for the long X-X distances, which occur in regions where a large number of interactions other than those in the complexes contribute to the D r) curve (Figs. 6 and 7). 

The PtCl42- and PdCl42 complexes have the same square-planar structure as the gold(III) halide complexes and concentrated solutions of each of them can be prepared. In crystal structures the Pt—Cl and the Pd—Cl bond lengths in these complexes do not differ significantly and their solution diffraction curves show this to be true also in solution. They can, therefore, be expected to form isostructural solutions and the difference between the normalized diffraction curves for a platinate(II) 

The part of the distribution function that includes the nonmetal interactions only, is the dominant part, as shown by the comparison in Fig. 10, but has much less distinct features than the part involving the metal atom interactions. It shows diffuse peaks in the region around 3.0 A, which can be related to H20—H20, Cl—H20, and Cl—Cl dis- 

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Reduced intensity curves, gold(III) halide solutions, 39 170... 

Fig. 5. Experimental s-i(s) values (crosses) for gold(III) halide solutions compared with theoretical values (solid lines) calculated for square-planar AuX4 complexes.

Fig. 6. Radial distribution functions, D(r), for the gold(III) halide solutions (solid lines), compared with calculated peaks (dots) for a square-planar AuX,t complex. The 47rr2p0 functions are shown by dotted lines. 

Halides. Gold(III) chloride [13453-07-1] can be prepared directiy from the elements at 200°C (167). It exists as the chlotine-bridged dimer, Au2Clg ia both the soHd and gas phases under an atmospheric pressure of chlorine at temperatures below 254°C. Above this temperature ia a chlorine atmosphere or at lower temperatures ia an iaert atmosphere, it decomposes first to AuCl [10294-29-8] and then to gold. The monochloride is only metastable at room temperature and slowly disproportionates to gold(0) and gold(III) chloride. The disproportionation is much more rapid ia water both for AuCl and the complex chloride, [AuCy, formed by iateraction with metal chlorides ia solution. 

Aqueous solutions of triorgano telluronium halides formed precipitates when mixed with aqueous solutions of copper(II) chloride zinc(II) chloride , gold(III) chloride ", mercury(II) halides " , and tin(II) chloride. Analytical data are only available for the mercury compounds. These data indicate that equimolar amounts of the telluronium halide and the mercury halide combine. The reactions can also be carried out in ethanol" . 

These extractants require the presence of stable anionic metal complexes to form the extractable ion pair complexes, so that only metals that produce such species can be extracted with these compounds. The ease of metal extraction follows the mag-nitnde of the formation coefQcient of the anionic complex. Thus, in halide solution, gold (III) > iron (III) > zinc > cobalt > copper > nickel. 

This simple rule is broadly applicable to the chemistry of palladium(II) and platinum(II) and also to isomerization reactions of square-planar iridium(I), rhodium(I) and gold(III) complexes. However, there are exceptions. In complexes of the type [MX2L2] (M = Pd, Pt X = halide L = phosphine, thioether) the favored direction of isomerization is highly dependent upon the nature of the phosphine or thioether. The favored direction of isomerization reactions in solution is, of course, dependent upon solvent polarity in cases where a pair of isomers exhibit different dipole moments. 

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