Rhenium trioxide

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Rhenium trioxide
Rhenium-trioxide-unit-cell-3D-balls-B.png
REO3.JPG
Names
IUPAC name
Rhenium trioxide
Other names
Rhenia
Identifiers
3D model (JSmol)
ECHA InfoCard 100.013.845 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 215-228-8
PubChem CID
UNII
  • InChI=1S/3O.Re
  • O=[Re](=O)=O
Properties
ReO3
Molar mass 234.205 g/mol
AppearanceDeep red crystals
Density 6.92 g/cm3
Melting point 400 °C (752 °F; 673 K) (decomposes)
+16.0·10−6 cm3/mol
1.68
Structure
Cubic, cP4
Pm3m, No. 221
a = 374.8 pm
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Rhenium trioxide or rhenium(VI) oxide is an inorganic compound with the formula ReO3. It is a red solid with a metallic lustre that resembles copper in appearance. It is the only stable trioxide of the Group 7 elements (Mn, Tc, Re).

Contents

Preparation and structure

Rhenium trioxide can be formed by reducing rhenium(VII) oxide with carbon monoxide at 200 °C or elemental rhenium at 400 °C. [1]

Re2O7 + CO → 2 ReO3 + CO2
3 Re2O7 + Re → 7 ReO3

Re2O7 can also be reduced with dioxane. [2]

blue: Rhenium, red: Oxygen Rhenium-trioxide-3D-vdW.png
blue: Rhenium, red: Oxygen
ReO3 polyhedra Rhenium trioxide polyhedra.png
ReO3 polyhedra

Rhenium trioxide crystallizes with a primitive cubic unit cell, with a lattice parameter of 3.742 Å (374.2 pm). The structure of ReO3 is similar to that of perovskite (ABO3), without the large A cation at the centre of the unit cell. Each rhenium center is surrounded by an octahedron defined by six oxygen centers. These octahedra share corners to form the 3-dimensional structure. The coordination number of O is 2, because each oxygen atom has 2 neighbouring Re atoms. [3]

Properties

Physical properties

ReO3 is unusual for an oxide because it exhibits very low resistivity. It behaves like a metal in that its resistivity decreases as its temperature decreases. At 300 K, its resistivity is 100.0 nΩ·m, whereas at 100 K, this decreases to 6.0 nΩ·m, 17 times less than at 300 K. [3]

Chemical properties

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
2O
7. In concentrated nitric acid, it yields perrhenic acid. Upon heating to 400 °C under vacuum, it undergoes disproportionation: [2]

3 ReO3 → Re2O7 + ReO2

Rhenium trioxide can be chlorinated to give rhenium trioxide chloride: [4]

2 ReO3 + Cl2 → 2 ReO3Cl

Uses

Hydrogenation catalyst

Rhenium trioxide finds some use in organic synthesis as a catalyst for amide reduction. [5]

Related Research Articles

<span class="mw-page-title-main">Rhenium</span> Chemical element, symbol Re and atomic number 75

Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. Rhenium has the third-highest melting point and second-highest boiling point of any element at 5869 K. Rhenium resembles manganese and technetium chemically and is mainly obtained as a by-product of the extraction and refinement of molybdenum and copper ores. Rhenium shows in its compounds a wide variety of oxidation states ranging from −1 to +7.

<span class="mw-page-title-main">Copper(II) oxide</span> Chemical compound – an oxide of copper with formula CuO

Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.

<span class="mw-page-title-main">Chromium trioxide</span> Chemical compound

Chromium trioxide (also known as chromium(VI) oxide or chromic anhydride) is an inorganic compound with the formula CrO3. It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name. This compound is a dark-purple solid under anhydrous conditions and bright orange when wet. The substance dissolves in water concomitant with hydrolysis. Millions of kilograms are produced annually, mainly for electroplating. Chromium trioxide is a powerful oxidiser, a mutagen, and a carcinogen.

Molybdenum trioxide describes a family of inorganic compounds with the formula MoO3(H2O)n where n = 0, 1, 2. These compounds are produced on the largest scale of any molybdenum compound. The anhydrous oxide is a precursor to molybdenum metal, an important alloying agent. It is also an important industrial catalyst. It is a yellow solid, although impure samples can appear blue or green.

<span class="mw-page-title-main">Phosphorous acid</span> Chemical compound

Phosphorous acid (or phosphonic acid (singular)) is the compound described by the formula H3PO3. This acid is diprotic (readily ionizes two protons), not triprotic as might be suggested by this formula. Phosphorous acid is an intermediate in the preparation of other phosphorus compounds. Organic derivatives of phosphorous acid, compounds with the formula RPO3H2, are called phosphonic acids.

<span class="mw-page-title-main">Perrhenic acid</span> Chemical compound

Perrhenic acid is the chemical compound with the formula Re2O7(H2O)2. It is obtained by evaporating aqueous solutions of Re2O7. Conventionally, perrhenic acid is considered to have the formula HReO4, and a species of this formula forms when rhenium(VII) oxide sublimes in the presence of water or steam. When a solution of Re2O7 is kept for a period of months, it breaks down and crystals of HReO4·H2O are formed, which contain tetrahedral ReO−4. For most purposes, perrhenic acid and rhenium(VII) oxide are used interchangeably. Rhenium can be dissolved in nitric or concentrated sulfuric acid to produce perrhenic acid.

<span class="mw-page-title-main">Terbium(III,IV) oxide</span> Chemical compound

Terbium(III,IV) oxide, occasionally called tetraterbium heptaoxide, has the formula Tb4O7, though some texts refer to it as TbO1.75. There is some debate as to whether it is a discrete compound, or simply one phase in an interstitial oxide system. Tb4O7 is one of the main commercial terbium compounds, and the only such product containing at least some Tb(IV) (terbium in the +4 oxidation state), along with the more stable Tb(III). It is produced by heating the metal oxalate, and it is used in the preparation of other terbium compounds. Terbium forms three other major oxides: Tb2O3, TbO2, and Tb6O11.

<span class="mw-page-title-main">Ammonium perrhenate</span> Chemical compound

Ammonium perrhenate (APR) is the ammonium salt of perrhenic acid, NH4ReO4. 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 NH4Cl. It was first described soon after the discovery of rhenium.

<span class="mw-page-title-main">Manganese heptoxide</span> Chemical compound

Manganese(VII) oxide (manganese heptoxide) is an inorganic compound with the formula Mn2O7. This volatile liquid is highly reactive. It is a dangerous oxidizer and was first described in 1860. It is the acid anhydride of permanganic acid.

<span class="mw-page-title-main">Antimony pentoxide</span> Chemical compound

Antimony pentoxide (molecular formula: Sb2O5) is a chemical compound of antimony and oxygen. It contains antimony in the +5 oxidation state.

<span class="mw-page-title-main">Palladium(II) oxide</span> Chemical compound

Palladium(II) oxide is the inorganic compound of formula PdO. It is the only well characterised oxide of palladium. It is prepared by treating the metal with oxygen. Above about 900 °C, the oxide reverts to palladium metal and oxygen gas. It is not attacked by acids.

<span class="mw-page-title-main">Rhenium(VII) oxide</span> Chemical compound

Rhenium(VII) oxide is the inorganic compound with the formula Re2O7. This yellowish solid is the anhydride of HOReO3. Perrhenic acid, Re2O7·2H2O, is closely related to Re2O7. Re2O7 is the raw material for all rhenium compounds, being the volatile fraction obtained upon roasting the host ore.

<span class="mw-page-title-main">Rhenium(IV) oxide</span> Chemical compound

Rhenium(IV) oxide or rhenium dioxide is the inorganic compound with the formula ReO2. This gray to black crystalline solid is a laboratory reagent that can be used as a catalyst. It adopts the rutile structure.

The perrhenate ion is the anion with the formula ReO−
4, or a compound containing this ion. The perrhenate anion is tetrahedral, being similar in size and shape to perchlorate and the valence isoelectronic permanganate. The perrhenate anion is stable over a broad pH range and can be precipitated from solutions with the use of organic cations. At normal pH, perrhenate exists as metaperrhenate, but at high pH mesoperrhenate forms. Perrhenate, like its conjugate acid perrhenic acid, features rhenium in the oxidation state of +7 with a d0 configuration. Solid perrhenate salts takes on the color of the cation.

Organorhenium chemistry describes the compounds with Re−C bonds. Because rhenium is a rare element, relatively few applications exist, but the area has been a rich source of concepts and a few useful catalysts.

<span class="mw-page-title-main">Chromyl fluoride</span> Chemical compound

Chromyl fluoride is an inorganic compound with the formula CrO2F2. It is a violet-red colored crystalline solid that melts to an orange-red liquid.

Copper(I) sulfate, also known as cuprous sulfate, is an inorganic compound with the chemical formula Cu2SO4. It is a white solid, in contrast to copper(II) sulfate, which is blue in hydrous form. Compared to the commonly available reagent, copper(II) sulfate, copper(I) sulfate is unstable and not readily available.

<span class="mw-page-title-main">Gold(I) cyanide</span> Chemical compound

Gold(I) cyanide is the inorganic compound with the chemical formula AuCN. It is the binary cyanide of gold(I). It is an odourless, tasteless yellow solid. Wet gold(I) cyanide is unstable to light and will become greenish. Gold(I) cyanide itself is only of academic interest, but its derivative dicyanoaurate is an intermediate in gold cyanidation, the extraction of gold from its ores.

Rhenium compounds are compounds formed by the transition metal rhenium (Re). 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, +6, +4, and +2 are the most common. Rhenium is most available commercially as salts of perrhenate, including sodium and ammonium perrhenates. These are white, water-soluble compounds. Tetrathioperrhenate anion [ReS4]− is possible.

<span class="mw-page-title-main">Rhenium trioxide chloride</span> Chemical compound

Rhenium trioxide chloride is an inorganic compound with the formula ReO3Cl. It is a colorless, distillable, diamagnetic liquid. It is arhenium oxychlorides. The material is used as a reagent in the preparation of rhenium compounds.

References

  1. ↑ H. Nechamkin, C. F. Hiskey, "Rhenium(VI): Oxide (Rhenium Trioxide)" Inorganic Syntheses, 1950 Volume 3, pp. 186-188. doi : 10.1002/9780470132340.ch49
  2. 1 2 O. Glemser; R. Sauer (1963). "Rhenium(VI) Oxide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2pages=1482. NY,NY: Academic Press.
  3. 1 2 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8., p. 1047.
  4. ↑ O. Glemser; R. Sauer (1963). "Rhenium (VII) Oxychloride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2pages=1480. NY,NY: Academic Press.
  5. ↑ Nishimura, Shigeo (2001). Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis (1st ed.). New York: Wiley-Interscience. p. 408. ISBN   9780471396987.
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