THE ATOMIC WEIGHT OF INDIUM

L. M. Dennis, W. C. Geer
1904 Journal of the American Chemical Society  
TEE publication of a preliminary note by A. Thiell upon "The Atomic Weight and Some New Compounds of Indium" leads the authors to describe briefly the results of an investigation, begun some months ago and not yet completed, upon the same subject. The indium used in our work was purchased on the market in the metallic form. In studying methods for its purification for the atomic weight determinations that are now being carried forward the following observations have been made : Iron can be
more » ... : Iron can be separated from indium by adding potassium sulphocyanate to a slightly acid solution of the chlorides of the two metals, and separating the ferric sulphocyanate by shaking up this aqueous solution with etner. The removal of iron by this method is complete, but the ether solution of the ferric sulphocyanate contains traces of indium. Anhydrous ferric chloride and anhydrous aluminum chloride in alcoholic solutions give no precipitate with pyridine. Anhydrous indium chloriae in alcoholic solution gives with pyridine a heavy white precipitate. This precipitate is soluble in a rather large excess of pyridine, is difficultly soluble in absolute alcohol, and difficultly soluble in ether. It is changed by water to the flocculent indium hydroxide. This change is facilitated by warming the precipitate. Commercial indium, when dissolved in hydrochloric acid, evaporated to dryness on the water-bath, and, taken up with absolute alcohol, gave, with pyridine, this white precipitate which, when tested with potassium sulphwyanate, showed no iron, although the solution from which the indium was precipitated reacted strongly for iron. An aqueous solution of hydroxylamine precipitates gelatinous indium hydroxide. In the presence of hydroxylamine hydrochloride, hydroxylamine produces no precipitate. The ordinary yellow indium oxide is reduced by dry ammonia 1 B n . d. chrm Ges., 37, 175 (1904)
doi:10.1021/ja01994a013 fatcat:kp7enduemnhybifphospwitvdm