Rhenium(VII) oxide

Rhenium(VII) oxide
Names
	Other names Rhenium heptoxide
Identifiers
CAS Number	1314-68-7 ;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.013.857
PubChem CID	123106;
UNII	0DJ421156F ;
CompTox Dashboard (EPA)	DTXSID00894901 ;
	InChI InChI=1S/7O.2Re;
	SMILES O=[Re](=O)(=O)O[Re](=O)(=O)=O;
Properties
Chemical formula	Re2O7
Molar mass	484.40298 g/mol
Appearance	yellow crystalline powder
Density	6.103 g/cm3, solid
Melting point	360 °C (680 °F; 633 K)
Boiling point	sublimes
Hazards
EU classification (DSD) (outdated)	not listed
Related compounds
Related compounds	Manganese(VII) oxide; technetium(VII) oxide; perrhenic acid
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Rhenium(VII) oxide is the inorganic compound with the formula Re₂ O₇. 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.^[1]

Structure

Solid Re₂O₇ consists of alternating octahedral and tetrahedral Re centres. Upon heating, the polymer cracks to give molecular (nonpolymeric) Re₂O₇. This molecular species closely resembles manganese heptoxide, consisting of a pair of ReO₄ tetrahedra that share a vertex, i.e., O₃Re-O-ReO₃.^[2]

Synthesis and reactions

Rhenium(VII) oxide is formed when metallic rhenium or its oxides or sulfides are oxidized at 500-700 °C in air.^[3]

Re₂O₇ dissolves in water to give perrhenic acid. It is a precursor to methylrhenium trioxide ("MTO"), a catalyst for oxidations.^[4]

Uses

Hydrogenation catalyst

Rhenium(VII) oxide finds some use in organic synthesis as a catalyst for ethenolysis,^[5] carbonyl reduction and amide reduction.^[6]

References

^ Hans Georg Nadler "Rhenium and Rhenium Compounds" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000. doi:10.1002/14356007.a23_199
^ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
^ Schmidt, Max; Schmidbaur, Hubert (1967). "Trimethylsilyl Perrhenate". Inorganic Syntheses. 9: 149–151. doi:10.1002/9780470132401.ch40. ISBN 9780470132401.
^ W. A. Herrmann and F. E. Kuhn (1997). "Organorhenium Oxides". Acc. Chem. Res. 30 (4): 169–180. doi:10.1021/ar9601398.
^ Lionel Delaude, Alfred F. Noels. "Metathesis". Kirk-Othmer Encyclopedia of Chemical Technology. Wiley.
^ Nishimura, Shigeo (2001). Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis (1st ed.). New York: Wiley-Interscience. pp. 42–43, 182, 389–390, & 408. ISBN 9780471396987.

[1] Hans Georg Nadler "Rhenium and Rhenium Compounds" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000. doi:10.1002/14356007.a23_199

[2] Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.

[3] Schmidt, Max; Schmidbaur, Hubert (1967). "Trimethylsilyl Perrhenate". Inorganic Syntheses. 9: 149–151. doi:10.1002/9780470132401.ch40. ISBN 9780470132401.

[4] W. A. Herrmann and F. E. Kuhn (1997). "Organorhenium Oxides". Acc. Chem. Res. 30 (4): 169–180. doi:10.1021/ar9601398.

[KO-5] Lionel Delaude, Alfred F. Noels. "Metathesis". Kirk-Othmer Encyclopedia of Chemical Technology. Wiley.

[6] Nishimura, Shigeo (2001). Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis (1st ed.). New York: Wiley-Interscience. pp. 42–43, 182, 389–390, & 408. ISBN 9780471396987.

[1]

[2]

[3]

[4]

[5]

[6]