Rhenium heptafluoride
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Names | |
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IUPAC name
rhenium heptafluoride, heptafluoridorhenium
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
ReF7 | |
Molar mass | 319.196 g/mol |
Appearance | Bright yellow crystalline solid |
Density | 4.3 g/cm3 |
Melting point | 48.3 °C (118.9 °F; 321.4 K) |
Boiling point | 73.72 °C (164.70 °F; 346.87 K) |
Reacts | |
Vapor pressure | 13.41 kPa[1] |
Structure | |
triclinic, aP16 | |
P1 (No. 2) | |
Thermochemistry | |
Enthalpy of fusion (ΔfH⦵fus)
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7.53 kJ/mol[1] |
Enthalpy of vaporization (ΔfHvap)
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30.77 kJ/mol[1] |
Related compounds | |
Related compounds
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Osmium heptafluoride |
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 heptafluoride is the compound with the formula ReF7. It is a yellow low melting solid and is the only thermally stable metal heptafluoride.[2] It has a distorted pentagonal bipyramidal structure similar to IF7, which was confirmed by neutron diffraction at 1.5 K.[3] The structure is non-rigid, as evidenced by electron diffraction studies.[4]
Production, reactions and properties
Rhenium heptafluoride can be prepared from the elements at 400 °C:[5]
- 2 Re + 7 F2 → 2 ReF7
It also can be produced by the explosion of rhenium metal under sulfur hexafluoride. [6]
It hydrolyzes under a base to form perrhenic acid and hydrogen fluoride:[1]
- ReF7 + 4H2O → HReO4 + 7HF
With fluoride donors such as CsF, the ReF−
8 anion is formed, which has a square antiprismatic structure.[7] With antimony pentafluoride, SbF5, a fluoride acceptor, the ReF+
6 cation is formed.[5]
References
- ^ a b c d J.G.Malm; H.Selig (1961). "The vapour-pressures and other properties of ReF6 and ReF7". Journal of Inorganic and Nuclear Chemistry. 20 (3): 189–197. doi:10.1016/0022-1902(61)80267-4.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Vogt T.; Fitch A. N.; Cockcroft J. K. (1994). "Crystal and Molecular Structures of Rhenium Heptafluoride". Science. 263 (5151): 1265–7. Bibcode:1994Sci...263.1265V. doi:10.1126/science.263.5151.1265. PMID 17817431. S2CID 20013073.
- ^ Jacob, E. Jean; Bartell, L.S.J. (1970). "Electron Diffraction Study of Rhenium Fluorides. II. Structure, Pseudorotation, and Anharmonic Coupling of Modes in ReF7" (PDF). The Journal of Chemical Physics. 53 (6): 2235. Bibcode:1970JChPh..53.2235J. doi:10.1063/1.1674318. hdl:2027.42/70852.
- ^ a b A. F. Holleman; Wiberg, Egon; Wiberg, Nils (2001). Inorganic Chemistry. Boston: Academic Press. ISBN 0-12-352651-5.
- ^ Richard L. Johnson; Bernard Siegel (1969). "On the synthesis of ReF7 and the existence of ReF2 and ReF3". Journal of Inorganic and Nuclear Chemistry. 31 (8): 2391–2396. doi:10.1016/0022-1902(69)80569-5.
- ^ Hwang, I; Seppelt, K. (2000). "The structures of ReF−
8 and UF2−
8". Journal of Fluorine Chemistry. 102 (1–2): 69–72. doi:10.1016/S0022-1139(99)00248-1.