Rhenium heptafluoride
Chemical compound
From Wikipedia, the free encyclopedia
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]
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| Names | |
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| IUPAC name
rhenium heptafluoride, heptafluoridorhenium | |
| 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) |
7.53 kJ/mol[1] |
Enthalpy of vaporization (ΔfHvap) |
30.77 kJ/mol[1] |
| Related compounds | |
Related compounds |
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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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]