Polonides metal

Although Po is distinctly metallic in some ways, [e.g., it forms saltlike Po11 and PoIV compounds such as PoCl2, PoBr2, Po(S04)2, and Po(Cr04)2] it also shows nonmetal characteristics by forming numerous polonides (MPo), which are often isostructural with tellurides and appear to be fairly ionic. 

The selenides and tellurides are similar to the sulfides, being preparable from ammonia solutions of the alkali metals. They are water-soluble yet partially hydrolyzed like the sulfides, but are more susceptible to oxidation back to the element. Not every member of the class M cSe3,/Te3, has been fully investigated, but the many that have promise few surprises see Selenium Inorganic Chemistry and Tellurium Inorganic Chemistry). The polonides are similar, and also have their own article see Polonium Inorganic Chemistry). 

By analogy with tellurium, which forms tellurides, the existence of polonides should be expected. Soluble tellurides, such as sodium telluride, are extremely sensitive to oxidation. Especially in solution, they revert rapidly to elemental tellurium. Because of its greater metallic character, polonides should oxidize even more rapidly than tellurides. Nevertheless, evidence has been presented for the existence of a number of polonides. 

Some solid compounds ol Po. e.p. PoCl.. indicate that it has meiatlic properties, but most of its chemistry is that ol metal polonides containing the Po ion... 

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