Rhenium heptafluoride

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Rhenium heptafluoride
ReF7 structure.png
Identifiers
CAS number 17029-21-9
PubChem 123369
Jmol-3D images Image 1
Properties
Molecular formula ReF7
Molar mass 319.196 g/mol
Appearance Bright yellow crystalline solid
Density 4.3g/cm3
Melting point 48.3°C
Boiling point 73.72°C
Structure
Crystal structure triclinic, aP16
Space group P-1, No. 2
Except where noted otherwise, 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[edit]

  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419. 
  2. ^ Vogt T., Fitch A. N., Cockcroft J. K. (1994). "Crystal and Molecular Structures of Rhenium Heptafluoride". Science 263 (5151): 1265. 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 b 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.