Polonium hydroxide

Metallic polonium has been prepared from polonium hydroxide and some other polonium compounds in the presence of concentrated aqueous or anhydrous liquid ammonia. Two allotropic modifications are known to exist. 

A white solid, possibly polonium tetrafluoride, is obtained by treating polonium hydroxide or tetrachloride with dilute aqueous hydrofluoric acid treatment of this solid, in suspension in dilute hydrofluoric acid, with sulfur dioxide yields a bluish grey product (possibly PoF2) which rapidly reverts to the original white solid on standing, presumably owing to radio-lytic oxidation 12). The solubility of polonium(IV) in aqueous hydrofluoric acid increases rapidly with acid concentration, indicating complex ion formation (/ft), p. 48). 

This is a white, gelatinous solid of composition close to 2Po02-H3P04, made by the action of 1 M diammouium phosphate on solid polonium tetrachloride or of 2 M phosphoric acid on polonium hydroxide. It appears... 

The treatment of polonium hydroxide with 2 N formic acid yields a black solid of uncertain composition and low solubility (11). 

Evidence for the existence of PoS is much stronger. Aqueous solutions in HCl containing Po and Po yield a precipitate of PoS. During the course of this reaction, Po is reduced to Po with the concurrent oxidation of sulfide to free sulfur. The same sulfide can be prepared by the reaction between polonium hydroxide and ammonium sulfide. The compound has not been successfully prepared by the direct reaction between the elements. 

An unidentiffed compound, not polonium hydroxide and presumed to be P0OCI2, was obtained by the evaporation of a dilute hydrochloride acid containing polonium. The residue is soluble in polar organic solvents such as ethanol, ethylene glycol, dioxane, acetone, and methyl ethyl ketone. It is insolnble in benzene or chloroform. 

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