Polonium Salts of Oxy-acids

Metallic polonium is not affected by 15% bromic acid, even at 70°C, and polonium dioxide or polonium(IV) hydroxide are only slightly soluble (2.5 mg Po02/liter) in 10% bromic acid. Polonium tetrachloride is converted to a white solid of unknown composition by 15% bromic acid this could be a basic chloride (12). 

Long treatment of polonium(IV) hydroxide with water saturated with carbon dioxide yields an unstable white solid, apparently a carbonate (12). 

The solubility of oxidized polonium—probably the dioxide—in aqueous sodium carbonate is about 0.3 mg (of Po210)/liter and does not change appreciably with the carbonate concentration. However, the solubility in aqueous ammonium carbonate increases from 0.089 mg (of Po210)/ liter in 0.25 M solution to 5.2 mg/liter in 0.75 M solution (104, P- 53). 

Aqueous 1 M chromium trioxide (12) does not react with metallic polonium, but with polonium(IV) hydroxide or tetrachloride yields an orange-yellow solid, thought to be Po(Cr04)2. This is insoluble in an excess of the reagent and is easily hydrolyzed by water or wet acetone to a dark brown basic chromate with a composition close to 2Po02 Cr()3 (cf., the basic sulfate and selenate). On long standing in an excess of aqueous chromium trioxide, oxidation to polonium(VI) may occur (Section VI,A). 

Polonium tetranitrate, with at least one molecule of dinitrogen tetroxide of crystallization, is formed as a white crystalline solid by the action of liquid dinitrogen tetroxide on polonium dioxide or tetrachloride polonium metal does not react with this reagent or with its solution in ethyl acetate. The dinitrogen tetroxide is rapidly lost on standing and the resulting tetranitrate decomposes to the basic salt (1) in l i 2 hr. under vacuum (16). 

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