US EPA

4193640 

Journal Article 

Measurements of diffusion coefficients of aqua- and chloro-complexes of palladium(II) and mercury(II) in aqueous solutions 

Uemoto, M 

2000 

0 

Inorganic Reaction Mechanisms
ISSN: 1028-6624 

2 

1-2 

155-159 

WOS:000166296700018 

Tracer-diffusion coefficients of aqua- and chlorocomplexes of palladium(II) and mercury(II) at 298.2 K in aqueous solutions have been measured, using the diaphragm cell technique with a fluorinated thin-membrane filter. Those of chloro-complexes were greater than those of the aqua-complexes, though chloride ion replaced is larger in radius than a hydrated water molecule. This indicates that the weakening of interaction between the complex ion and surrounding solvent water in a translational motion is accompanied by an increase in the diffusion coefficient. Individual diffusion coefficients of the complexes have been assigned to D (Pd2+) = 8.3, D (PdCl+) = 8.7, D (PdCl2) = 9.1, D (PdCl3-) = 9.4, D (PdCl42-) = 11.3, and D (Hg2+) = 9.2, D (HgCl+) = 11.1, D (HgCl2) = 12.3, D (HgCl3-) = 10.4, D (HgCl42-) = 11.5 (D in the unit of 10(-10) m(2) s(-1)). The processes of water-ligand replacement on complex formation are discussed. 

diffusion coefficients; diaphragm cell method; thin membrane filter; palladium complexes; mercury complexes