The Analytical Separation of Titanium from Tungsten, Together with a Study of the Heteropoly-Tungstates

The classical idea (based on a study of the boro-, silico- and phospho-tungstic acids) that each of the heteropoly-tungstic acids is formed by combination of tungstic acid with another acidic oxide can no longer be regarded as correct. The heteropoly-series now includes compounds formed by combination of tungstic oxide with oxides of definitely non-acidic character; and indeed elements of every Group, from I to VII, of the Periodic Table are now to be found in the heteropoly-tungstic series. Thus: in Group III because of its tervalency). Time did not permit of an attempt being made to prepare a heteropoly-tungstic acid containing one of the precious metals of Group VIII; but, in view of the behaviour of 7-valent chlorine, there seems to he no reason to doubt that tungsto-platinic or tungsto-osmic acid could be synthesised. In fact, the probability is that, of all the elements in the Periodic Table, only the Inert Gases, the Alkali Metals, and possibly the Alkaline Earths, are exempt from heteropoly-tungstic acid formation