Rhenium heptafluoride

Rhenium heptafluoride
Names

IUPAC name rhenium heptafluoride, heptafluoridorhenium
Identifiers
CAS Number	17029-21-9^Y
3D model (JSmol)	Interactive image
ChemSpider	26323924^N
PubChem CID	123369
UNII	H54U6B0W52^Y
CompTox Dashboard (EPA)	DTXSID50168826
InChI InChI=1S/7FH.Re/h71H;/q;;;;;;;+7/p-7^N Key: HFHBKXWKPQUYIA-UHFFFAOYSA-G^N InChI=1/7FH.Re/h71H;/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	4.3 g/cm³
Melting point	48.3 °C (118.9 °F; 321.4 K)
Boiling point	73.72 °C (164.70 °F; 346.87 K)
Solubility in water	Reacts
Vapor pressure	13.41 kPa^[1]
Structure
Crystal structure	triclinic, aP16
Space group	P1 (No. 2)
Thermochemistry
Enthalpy of fusion (Δ_fH^⦵_fus)	7.53 kJ/mol^[1]
Enthalpy of vaporization (Δ_fH_vap)	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). N verify (what is ^YN ?) Infobox references

Chemical compound

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.