Potassium Diuranate, K₂U₂O₇

Potassium Diuranate, K₂U₂O₇, is obtained in the anhydrous condition by heating potassium uranyl acetate or carbonate; or by fusing together uranium trioxide and potassium carbonate. It yields glistening crystals, which vary in colour from yellow to orange-red according to the mode of preparation. The trihydrate, K₂U₂O₇.3H₂O, is obtained by drying at 100° C. the yellow precipitate formed when excess of potassium hydroxide is added to a solution of a uranyl salt. According to Stolba, if the precipitate is allowed to dry in air at ordinary temperature, the hexahydrate, K₂U₂O₇.6H₂O, is formed.