POLAROGRAPHIC REDUCTION OF HEXAMMINECOBALT (III) ION. THE EFFECT OF NONCOMPLEXING ELECTROLYTES
Abstract
The formation of a Co(OH) sub 2 film was postulated to explain the dips appearing in the diffusion current region of the first reduction wave of Co(NH sub 3) sub 6 (3+) in perchlorate, chloride, and nitrate solutions. The film did not form after the addition of 0.02% gelatin, or with an increased concentration of the supporting electrolyte. The effects of various salts and of pH on the film formation are discussed. The addition of a small amount of Co(2+) during the reduction of Co(NH sub 3) sub 6 (3+) in the presence of aquated Co(2+) did not cause an addition to the second wave; Co(2+) was precipititated by the NH sub 3 which was released during the reduction of Co(NH sub 3) sub 6 (3+), indicating that the reduction to the metallic state occurs without a hexaaquo Co(2+) intermediate. In the presence of bromide, thiocyanate, or iodide ions, a film of Co(OH) sub 2 was formed by the direct interaction of Hg. The diffusion current of Co(NH sub 3) sub 6 (3+) was measured in supporting electrolytes of different charge type and known viscosity. The diffusion current was inversely proportional to the square root of the viscosity. The masking effect of viscosity on the diffusion rate was independent of the nature of the electrolyte, provided the charge of the ion was kept constant. The results indicated that, in addition to the effect of viscosity, there was a suppressing effect which increased with the increasing charge of anion. This effect is consistent with the concept of electrostatic clustering (Laitinen and other, J. Am. Chem. Soc. 70:2999, 1948).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 05, 1953
- Accession Number
- AD0001781
Entities
People
- A. J. Frank
- H. A. Laitinen
- P. Kivalo
Organizations
- University of Illinois Urbana–Champaign