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Rhenium(VI) oxide has an appearance similar to that of copper. Rhenium(IV) oxide (or rhenium dioxide) is an oxide of rhenium, with the formula ReO 2. This gray to black crystalline solid is a laboratory reagent that can be used as a catalyst. It adopts the rutile structure. It forms via comproportionation: [4] 2 Re 2 O 7 + 3 Re → 7 ReO 2
This compound reacts with water to produce perrhenic acid and nitric acid. [1] When heated above 75 °C, it decomposes to rhenium heptoxide, nitrogen dioxide, and oxygen: [1] 4 ReO 3 NO 3 → 2 Re 2 O 7 + 2 NO 2 + O 2. A graphite intercalation compound can be produced by reacting a mixture of rhenium trioxynitrate and dinitrogen pentoxide with ...
Rhenium is a chemical element; it has symbol Re and atomic number 75. It is a silvery-gray, ... It will however, react with nitric acid upon heating. [27] Isotopes
Rhenium trioxide is insoluble in water, as well as dilute acids and bases. Heating it in base results in disproportionation to give ReO 2 and ReO − 4, while reaction with acid at high temperature affords Re 2 O 7. In concentrated nitric acid, it yields perrhenic acid. Upon heating to 400 °C under vacuum, it undergoes disproportionation: [2]
Perrhenic acid is the chemical compound with the formula Re 2 O 7 (H 2 O) 2. It is obtained by evaporating aqueous solutions of Re 2 O 7 . Conventionally, perrhenic acid is considered to have the formula HReO 4 , and a species of this formula forms when rhenium(VII) oxide sublimes in the presence of water or steam. [ 2 ]
These salts are prepared by oxidation of rhenium compounds with nitric acid followed by neutralization of the resulting perrhenic acid. [2] [3] [4] Addition of tetrabutylammonium chloride to aqueous solutions of sodium perrhenate gives tetrabutylammonium perrhenate, which is soluble in organic solvents. [5]
The most reactive metals, such as sodium, will react with cold water to produce hydrogen and the metal hydroxide: 2 Na (s) + 2 H 2 O (l) →2 NaOH (aq) + H 2 (g) Metals in the middle of the reactivity series, such as iron , will react with acids such as sulfuric acid (but not water at normal temperatures) to give hydrogen and a metal salt ...
Ammonium perrhenate (APR) is the ammonium salt of perrhenic acid, NH 4 ReO 4. It is the most common form in which rhenium is traded. It is a white salt; soluble in ethanol and water, and mildly soluble in NH 4 Cl. [2] It was first described soon after the discovery of rhenium. [3]