Rhenium (VII) oxide

Crystal structure
	__ Re 7+ __ O 2−
Crystal system	orthorhombic
Space group	P 2 1 2 1 2 1 (No. 19)
Lattice parameters	a = 1250 pm, b = 1520 pm and c = 540 pm
General
Surname	Rhenium (VII) oxide
other names	Rhenium heptoxide
Ratio formula	Re 2 O 7
Brief description	yellow, almost odorless solid
External identifiers / databases
EC number	215-241-9
ECHA InfoCard	100,013,857
PubChem	123106
Wikidata	Q418325
properties
Molar mass	484.40 g mol −1
Physical state	firmly
density	6 g cm −3
Melting point	220 ° C
boiling point	363 ° C
solubility	Decomposes in water; insoluble in alcohols, ethers, amines, dimethyl sulfoxide, nitromethane, benzene and carbon tetrachloride at room temperature;
safety instructions
H and P phrases	H: 272-314
	P: 210-280-301 + 330 + 331-305 + 351 + 338-309 + 310
Thermodynamic properties
ΔH f 0	−1128 kJ mol −1
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Rhenium (VII) oxide Re ₂ O ₇ is a chemical compound and is one of the oxides of rhenium . It is a yellow, hygroscopic solid. Compared to the unstable and explosive manganese (VII) oxide , rhenium (VII) oxide is significantly more stable.

Extraction and presentation

Rhenium (VII) oxide is formed when rhenium or rhenium compounds are heated in air.

{\ displaystyle {\ ce {4Re + 7O2 -> 2Re2O7}}}

properties

Physical Properties

Rhenium (VII) oxide crystallizes in an orthorhombic crystal structure with the space group P 2 ₁ 2 ₁ 2 ₁ (space group no. 19) . The lattice constants are a = 1250 pm, b = 1520 pm and c = 540 pm. In the crystal , rhenium (VII) oxide forms ReO ₄ - tetrahedra and ReO ₆ - octahedron , which alternate and are linked via the corners. Template: room group / 19

Chemical properties

Rhenium (VII) oxide is very hygroscopic and dissolves well in water. When dissolving, the strong acid perrhenic acid is formed . Rhenium (VII) oxide is carried hydrogen at 300 ° C to rhenium (IV) oxide reduced.

use

Rhenium (VII) oxide is an intermediate product in the extraction of elemental rhenium. It is created when roasting manganese ores containing rhenium. The rhenium (VII) oxide is dissolved in water after separation from the remaining fly ash . From the resulting perrhenic acid, the rhenium is precipitated as ammonium perrhenate and reduced to the element with hydrogen .

Rhenium (VII) oxide can be used as a catalyst in various reactions in organic chemistry . With the help of rhenium (VII) oxide, alkanes can be converted into carboxylic acids . Other reactions catalyzed by rhenium (VII) oxide are metathesis reactions of olefins . The catalyst methyltrioxorhenium (MTO) can be obtained from rhenium (VII) oxide .

Individual evidence

↑ ^a ^b B. Krebs, A. Müller and H. Beyer: The Crystal Structure of Rhenium (VII) Oxide . In: Inorg. Chem. , 1969, 8, 3, pp. 436-443.
↑ ^a ^b ^c ^d ^e ^f ^g Data sheet rhenium (VII) oxide (PDF) from Merck , accessed on December 25, 2019.
↑ ^a ^b ^c Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1616.
^ AF Holleman , N. Wiberg : Inorganische Chemie . 103rd edition. Volume 2: Subgroup elements, lanthanoids, actinides, transactinides. Walter de Gruyter, Berlin / Boston 2016, ISBN 978-3-11-049590-4 , p. 1921 (Reading sample: Part C - Subgroup elements. Google book search ).
↑ M. Kirillova et al .: Group 5-7 transition metal oxides as efficient catalysts for oxidative functionalization of alkanes under mild conditions . In: Journal of Catalysis , 2007, 248, pp. 130-136.
↑ M. Onaka, T. Oikawa: Olefin Metathesis over Mesoporous Alumina-supported Rhenium Oxide Catalyst. In: Chemistry Letters 2002 , 850-851.
↑ W. Herrmann et al .: Inexpensive, efficient and environmentally friendly synthesis of the versatile catalyst methyltrioxorhenium (MTO) . In: Angew. Chem. , 2007, 119, pp. 7440-7442.

literature

AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , pp. 1628-1629.

[kristallstruktur-1] B. Krebs, A. Müller and H. Beyer: The Crystal Structure of Rhenium (VII) Oxide . In: Inorg. Chem. , 1969, 8, 3, pp. 436-443.

[Merck-2] ↑ ^a ^b ^c ^d ^e ^f ^g Data sheet rhenium (VII) oxide (PDF) from Merck , accessed on December 25, 2019.

[brauer-3] Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1616.

[4] AF Holleman , N. Wiberg : Inorganische Chemie . 103rd edition. Volume 2: Subgroup elements, lanthanoids, actinides, transactinides. Walter de Gruyter, Berlin / Boston 2016, ISBN 978-3-11-049590-4 , p. 1921 (Reading sample: Part C - Subgroup elements. Google book search ).

[5] M. Kirillova et al .: Group 5-7 transition metal oxides as efficient catalysts for oxidative functionalization of alkanes under mild conditions . In: Journal of Catalysis , 2007, 248, pp. 130-136.

[6] M. Onaka, T. Oikawa: Olefin Metathesis over Mesoporous Alumina-supported Rhenium Oxide Catalyst. In: Chemistry Letters 2002 , 850-851.

[7] W. Herrmann et al .: Inexpensive, efficient and environmentally friendly synthesis of the versatile catalyst methyltrioxorhenium (MTO) . In: Angew. Chem. , 2007, 119, pp. 7440-7442.