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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(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 ...
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]
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]
Being the conjugate base of a strong acid (nitric acid, pK a = -1.4), nitrate has modest Lewis basicity.Two coordination modes are common: unidentate and bidentate.Often, bidentate nitrate, denoted κ 2-NO 3, is bound unsymmetrically in the sense that one M-O distance is clearly bonding and the other is more weakly interacting. [2]
Nitric acid is a powerful oxidizer, which will dissolve a very small quantity of gold, forming gold(III) ions (Au 3+). The hydrochloric acid provides a ready supply of chloride ions (Cl −), which react with the gold ions to produce tetrachloroaurate(III) anions ([AuCl 4] −), also in solution. The reaction with hydrochloric acid is an ...
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]