Polonium trioxide

Trioxides of sulfur, selenium, and tellurium are well recognized, but polonium trioxide has yet to be prepared in weighable quantities. 

Within the sulfur sub-group, there are two main types of oxides, the dioxides X 02 (X = S, Se, Te, Po) and the trioxides X Os (X = S, Se, Te). In addition, sulfur also forms disulfur monoxide, S2O. Transient XO species are known in the gaseous phase for S, Se, and Te. Polonium forms a black monoxide PoO. 

The physical properties of the metal (Table II) resemble those of thallium, lead and bismuth, its neighbors in the Periodic Table, rather than those of tellurium, its lower homologue. The low melting and boiling points are particularly noteworthy an attempted study of the Hall effect in polonium metal has also been reported (90). In chemical properties the metal is very similar to tellurium, the most striking resemblance being in its reactions with concentrated sulfuric acid (or sulfur trioxide) and with concentrated selenic acid. The products are the bright red solids, PoSOs and... 

Fusion of polonium dioxide with a potassium chlorate/hydroxide mixture gives a bluish solid (colorless when hot) which is more soluble in water than the corresponding polonite (Po032 ) this presumably contains some potassium polonate. The trioxide may possibly be formed by strongly heating polonium dioxide and chromium trioxide in air (12). 

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 is a radioactive element that is difficult to study in the laboratory.) Oxygen has a tendency to accept two electrons to form the oxide ion (O ) in many ionic compounds. Sulfur, selenium, and tellurium also form dinegative anions (S, Se, and Te ). The elements in this group (especially oxygen) form a large number of molecular compounds with nonmetals. The important compounds of sulfur are SO2, SO3, and H2S. Sulfuric acid is formed when sulfur trioxide reacts with water ... 

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