Barium diuranate

Barium Diuranate, BaUjO, is obtained by heating barium uranyl acetate, or by heating together the green oxide and barium chlorate. It is obtained in a hydrated condition when ammonia is added to mixed solutions of barium chloride and uranyl nitrate, or when excess of baryta water is added to uranyl nitrate solution. It is a deep yellow crystalline powder. 

Calcium Uranate, CaUO, and calcium diuranate, CaUaO , are similar to the corresponding barium salts and may be prepared by similar methods. The diuranate is highly refractory and does not fuse at red heat. 

Magnesium Uranate, MgU04, and magnesium diuranate, MgUjOy, may be obtained by the methods described for the barium salts. The diuranate yields yellowish-green needle-shaped crystals. 

Strontium Uranate, SrUOi, and strontium diuranate, SrU207, are similar in properties and are prepared by similar methods to the corresponding barium and calcium salts. 

Trace quantities of uranium in aluminum were determined by Mackintosh and Jervis (55). Two methods were described, one utilizing fission product barium while the other used the reaction U (n,7)U , half-life 23.5 min. In the latter case, after simple chemistry, uranium was mounted as the diuranate. Fairly good agreement was obtained between the two methods, that using U being the more sensitive and requiring shorter irradiation periods. 

Both uranium(VI) and plutonium(VI) form oxoanions. Uranium gives mono-, di-, tri-, tetra-, penta- and hexa-uranates the common diuranates, MgUgOy, correspond only formally to the dichromates. Barium hydroxide precipitates the triplutonate, BaPugO o, from solutions containing PuOg. ... 

Derivation (pure oxide) Powdered uranium ore is digested with hot nitric-sulfuric acid mixture and filtered to remove the insoluble portion. Sulfate is precipitated from the solution with barium carbonate, and uranyl nitrate is extracted with ether. After re-extraction into water, it is heated to drive off nitric acid, leaving uranium trioxide. The latter is reduced with hydrogen to the dioxide. Can be prepared from uranium hexafluoride by treating with ammonia and subsequent heating of the ammonium diuranate. It is also recovered from phosphoric acid. 

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