アルミニウム化合物の研究 (第2報)

塩基性アルミニウム溶液の組成

抄録

It has been shown that the composition of the basic aluminum chloride solution prepared by different methods could conveniently be indicated by Al_2+n(OH)_3nCl₆. It was found that even when this n is the same, the neutralization velocity by acid was different according to the manner of preparation. Such a fact indicates that there is a difference in the degree of formation of ol-bridge by the complex ions present in equilibrium. Therefore, the properties of the substance formed from the solution of the same basicity by SO₄^-- would probably be different.
Basic aluminum solutions were titrated with acid and alkali and their pH curves were found to show some specificity. Especially, titration with alkali was found to give the second breaking point at pH 5-6, besides the first breaking point at pH on the formation of aluminum hydroxide. This second point appears the sooner, the larger the value of n, and it was assumed that this second point was caused by the formation of [Al₃(OH₂)_x(OH)₈]⁺.