Rhenium heptafluoride

Rhenium heptafluoride

Names
IUPAC name rhenium heptafluoride, heptafluoridorhenium
Identifiers
CAS Number	17029-21-9
ChemSpider	26323924
Jmol interactive 3D	Image
PubChem	123369
InChI InChI=1S/7FH.Re/h7*1H;/q;;;;;;;+7/p-7 Key: HFHBKXWKPQUYIA-UHFFFAOYSA-G InChI=1/7FH.Re/h7*1H;/q;;;;;;;+7/p-7/rF7Re/c1-8(2,3,4,5,6)7 Key: HFHBKXWKPQUYIA-KLJGHBABAK
SMILES F[Re](F)(F)(F)(F)(F)F
Properties
Chemical formula	ReF7
Molar mass	319.196 g/mol
Appearance	Bright yellow crystalline solid
Density	4.3g/cm^3
Melting point	48.3 °C (118.9 °F; 321.4 K)
Boiling point	73.72 °C (164.70 °F; 346.87 K)
Structure
Crystal structure	triclinic, aP16
Space group	P-1, No. 2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Rhenium heptafluoride is the compound with the formula ReF₇. It is a yellow low melting solid, and is the only thermally stable metal heptafluoride.^[1] It has a distorted pentagonal bipyramidal structure similar to IF₇, which was confirmed by neutron diffraction at 1.5K.^[2] The structure is non-rigid as evidenced by electron diffraction studies.^[3]

It can be prepared from the elements at 400 °C:^[4]

2Re + 7 F₂ → 2 ReF₇

With fluoride donors such as CsF, the ReF₈⁻ anion is formed, which has a square antiprismatic structure.^[5] With antimony pentafluoride, SbF₅, a fluoride acceptor, the ReF₆⁺ cation is formed.^[4]

References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
2. Vogt T., Fitch A. N., Cockcroft J. K. (1994). "Crystal and Molecular Structures of Rhenium Heptafluoride". Science 263 (5151): 1265–7. doi:10.1126/science.263.5151.1265. PMID 17817431.
3. Jacob, E. Jean; Bartell, L.S.J. (1970). "Electron Diffraction Study of Rhenium Fluorides. II. Structure, Pseudorotation, and Anharmonic Coupling of Modes in ReF7". The Journal of Chemical Physics 53 (6): 2235. doi:10.1063/1.1674318.
4. A. F. Holleman; Wiberg, Egon; Wiberg, Nils (2001). Inorganic Chemistry. Boston: Academic Press. ISBN 0-12-352651-5.
5. Hwang, I; Seppelt, K. (2000). "The structures of ReF₈⁻ and UF₈²⁻". Journal of Fluorine Chemistry 102: 69. doi:10.1016/S0022-1139(99)00248-1.