Zur Frage nach der Existenz der neuartigen Mischkristalle von dem Typus BaSO₄ und KMn₄

STUDIES ON AGING OF FRESH PRECIPITATES. XVIII: The Mixed-crystal Formation Between Barium Sulfate and Potassium Permanganate

“…Briefly, they found that the crystals were homogeneously colored; that the permanganate in the crystals was inert towards various reagents; that the rate of solution in concentrated sulfuric acid increased with the potassium permanganate content of the crystals; that the amount of potassium permanganate in the crystals was approximately proportional to the concentration of potassium permanganate in the precipitating solutions; that it was possible to obtain precipitates containing as much as 80 mole per cent of potassium permanganate; that the x-ray pictures made by the Debye method showed a regular displacement of lines (6,11), such as would be produced if the potassium permanganate were "dissolved in the barium sulfate lattice; finally, that equivalent amounts of potassium and permanganate are coprecipitated. The latter fact is strongly indicative of mixed-crystal formation; the results of the x-ray investigation of Wagner (6,11), however, give conclusive evidence of the formation of solid solutions of potassium permanganate in barium sulfate.1 Various authors (1,2,3) have tried to invalidate Grimm's conclusions. Balarew (1), for example, criticizes Grimm's work and attributes the coprecipitation of potassium permanganate to an internal adsorption during the growth of barium sulfate.…”