Abstract
A study of previous investigations into the polarographic behaviour of antimony compounds reveals a number of gaps and inconsistencies in existing knowledge of the subject. These investigations are reviewed and critically discussed, and the conclusions drawn are applied to the practical studies reported in Section 3. A study of the influence,on polarographic studies,of impurities in electrode-mercury shows that such impurities affect the peak-heights, peak-potentials and half-peak pot ential spans. The nature, properties,methods of detection, and of removal are investigated and suitable procedures devised for testing and purifying the mercury to be used in these studies. By using purified mercury,coupled anodic/cathodic waves have been obtained for trivalent antimony in normal alkali which are free from the gross distortions and interfering waves previously reported in the literature. The polarographic characteristics of these waves have been investigated using alternating-voltage,alternating- current and linear-sweep oscillographic techniques, with sinusoidal and square-wave potential forms. With the aid of these techniques it has been found possible to obtain data on values,reversibilities and other reaction data. This work is described in Section3,Paris IV, V and VI. In Part VII, The design and construction of a new electrode of constant surface area, but with a renewable surface ,and suitable for hydrofluoric acid media,is desribed. Investigations with this electrode into the polarographic behaviour of hydrofluoric acid (1.0 N.) as a supporting electrolyte, and into the behaviour of antimony compounds in this media have shown that this combination permits electrode reactions to occur which produce polarographic waves. The characteristics of some of these waves have been determined. In addition, two new polarographic peaks for trivalent antimony in acetic adid (1.0 N.) have been discovered and their characteristics are reported,with additional data on the known peaks, in Section 3,Part VIII. In Section 3. Part IX, a study is reported into the nature of a very slight irregularity detected in the published polarograms for the reduction of trivalent antimony in nitric acid (1.0 N.) media. These studies showed that this irregularity was a pre-wave. Using square-wave polarography ,it has been possible to determine the characteristics of both pre-wave and main wave.