Rhenium oxide

Rhenium anhydride r2o7, rhenium trioxide reo3 and rhenium dioxide have practical significance.
In addition, the oxides of RE2O3, REO and Re2O8 were also studied. The existence of re2o5, reo4 or Re2O8 is still controversial.
Rhenium anhydride Re2O7 is formed during oxidation or metal plating of low rhenium compounds (e.g., res2). It is a light yellow solid that dissipates rapidly in air and dissolves in water to form rhenium acid of hreo4. Rhenium anhydride melts at 297 ° and does not decompose at 363 ° boiling point. Only about 600 ° was observed for dissociation. The heat of formation of Re2O7 is 295 kcal / mol. Carbon, hydrogen sulfide and hydrogen sulfide reduce Re2O7 to lower oxides. At 800 ℃, hydrogen will reduce Re2O7 to metal. Re27 is condensed in the form of hexagonal crystals.

Reo3 nitrous oxide is a red light crystalline metallic luster. Rhenium is mixed with Re2O7 in the absence of air under heating (200-250 °).
3Re2O7+Re=7ReO3.
Reo3 can exist in the intermediate products recovered from Re2O7 and can be produced in the case of incomplete combustion. Reo3 produces heat of 83 kcal, which is easily oxidized to Re2O7. There is no Reynolds 3 in the water. The corresponding rhenium acid h2reo4 and its salts are unstable.

Rhenium dioxide reo2 is a black (almost black) solid. Under heating conditions of Re2O7 hydrogen or Re2O7 or Re2O7 powder mixture at 600-650 ° the results are as follows:

3Re+2Re2O7=7ReO2.

The hydrate (OH) 4 of rhenium oxide (RE) is a dark brown precipitate, which can be reduced when zinc rhenium acid solution is reduced in hydrochloric acid environment. Hydrazine, and electrolysis.

Hydroxides exhibit amphoteric properties, but their acidity and basic functions are also weak. Reo2 is insoluble in water.



 

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