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Rhenium can form in many oxidation states, and compounds are known for every oxidation state from -3 to +7 except -2, although the oxidation states +7, +4, and +3 are the most common. [1] Rhenium is most available commercially as salts of perrhenate, including sodium and ammonium perrhenates. These are white, water-soluble compounds. [2]
Rhenium(IV) oxide or rhenium dioxide is the inorganic compound 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.
Rhenium compounds are known for all the oxidation states between −3 and +7 except −2. The oxidation states +7, +4, and +3 are the most common. [32] Rhenium is most available commercially as salts of perrhenate, including sodium and ammonium perrhenates. These are white, water-soluble compounds. [33] Tetrathioperrhenate anion [ReS 4] − is ...
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.
2 NH 4 ReO 4 + 7 H 2 → 2 Re + 8 H 2 O + 2 NH 3. Ammonium perrhenate decomposes to volatile Re 2 O 7 starting at 250 °C. When heated in a sealed tube at 500 °C, It decomposes to rhenium dioxide: [1] 2NH 4 ReO 4 → 2ReO 2 + N 2 + 4 H 2 O. The ammonium ion can be displaced with some concentrated nitrates e.g. potassium nitrate,, silver ...
Rhenium exists in ten known oxidation states from −3 to +7 except −2, and all but Re(−3) are represented by organorhenium compounds. Most are prepared from salts of perrhenate and related binary oxides. [ 1 ]
This yellow, air-stable solid is a precursor to a variety of other rhenium complexes. [1] In this diamagnetic compound, Re has an octahedral coordination environment with one oxo, three chloro and two mutually trans triphenylphosphine ligands. The oxidation state of rhenium is +5 and its configuration is d 2.
[1] [2] It can be obtained by reacting excess neodymium oxide with 240 g/L perrhenic acid solution. [3] In its solution, NdReO 4 2+ and Nd(ReO 4) 2+ can be observed with stability constants of 16.5 and 23.6, respectively. [4] Nd 4 Re 6 O 19 can be obtained by reacting neodymium perrhenate and NdRe 2 at high temperature. [5]