Pentafluorosulfate(IV)

Pentafluorosulfate(IV)
Chemical structure of pentafluorosulfate(IV) anion
Identifiers
3D model (JSmol)
  • InChI=1S/F5S/c1-6(2,3,4)5/q-1
  • Key: XYHBJTMLVHIFKZ-UHFFFAOYSA-N
  • F[S-](F)(F)(F)F
Properties
F5S−
Molar mass 127.05 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Pentafluorosulfite or pentafluorosulfate(IV) is an anion with formula [SF5]−.

Most pentafluorosulfite salts are unstable, decaying info SF4 gas and a fluoride salt. So for example, tetramethyl ammonium pentafluorosulfite has a vapour pressure of 2-3 mm Hg of SF4.

Formation

Some salts can be formed by reacting SF4 gas at low temperature with the fluoride salt.

Properties

[[]] Pentafluorosulfites are decomposed by water, but may be soluble in dimethylformamide.

The ion has a square pyramidal shape with C4v symmetry. The ion has a very similar spectrum and force constants to ClF5, and the spectrum is similar in form to other pentafluorides with a lone pair of electrons.

Force constants derived from the IR and Raman spectrum are: fR = 4.12 mdyn/Å, fr = 2.06 mdyn/Å, fα = 2.26 mdyn/Å radian, fβ = 0.86 mdyn/Å radian, frr' = 0.52, fββ' = 0.55 mdyn/Å radian, fαα' = 0.11 mdyn/Å radian, frr =0.23 mdyn/Å radian, fRβ =0.25mdyn/Å radian, frβ =0.15, frβ mdyn/Å radian, fββ = −0.20 mdyn/Å radian2.

Spectrum
point group assignment description band id IR band cm−1 Raman line cm−1
A1 vibration S-F axial v1 793 796
A1 vibration S-F4 equatorial v2 520 522
A1 deformation S-F4 umbrella v3 466 469
B1 stretch S-F4 out of phase v4 - 435 overlap
B1 S-F4 out of plane v5 - 269
B2 deformation S-F4 in plane v6 - 342
E vas v7 590 590
E deformation F'-S-F4 v8 430 435 overlap
E deformation as SF4 in plane v9 - 241

Reactions

Trichloroisocyanuric acid can react with pentafluorosulfite to form SF5Cl.

Selenium and tellurium also form similar anions SeF−5 and TeF−5. The general term for these is pentafluorochalcogenate(IV) anions. In organic chemistry the -SF5 group is called pentafluoro-λ6-sulfane or pentafluorosulfane, or as a prefix: pentafluoro-λ6-sulfanyl or pentafluorosulfanyl.

List

formula crystal system space group unit cell cell volume density comment ref
[(CH3)4N+]SF5− tetragonal P4/n a=13.503 c=19.471 Z=4 3550.2 1.48
[(tmg)3PF]+SF5− tmg=tetramethylguanidyl dissolve in THF or 1,2-difluorobenzene
[(R1)3PF]+SF5− R1 = 1,3-di-tert-butylimidazolidin-2-ylidenamino
Rb+SF5− orthorhombic Pbnm a = 7.76 b = 9.903 c = 6.141 Z = 4
trans,trans-[Rh(Cl)2(CO)(IMes)2][SF5] deep red; decomposes at room temperature
trans-[Rh(Cl)(F)(CO)(IMes)2][SF5] decomposes at room temperature
Cs+SF5− tetrahedral P4b2 a = 10.32 c = 6.276 Z = 1
(Cs+)6(SF5−)4 (HF2−)2
[Cs+.(18-crown-6)2] [SF5−]
[Cs(tetraglyme)2][SF5] tetrahedral P421c a =13.1515 c=17.792

References

  1. 1 2 3 4 Tunder, R.; Siegel, B. (September 1963). "The SF5 anion". Journal of Inorganic and Nuclear Chemistry. 25 (9): 1097–1098. doi:10.1016/0022-1902(63)80128-1.
  2. 1 2 3 4 5 6 Christe, Karl O.; Curtis, E. C.; Schack, Carl J.; Pilipovich, D. (July 1972). "Vibrational spectra and force constants of the square-pyramidal anions SF5-, SeF5-, and TeF5-". Inorganic Chemistry. 11 (7): 1679–1682. doi:10.1021/ic50113a046.
  3. ↑ Eder, Tobias; Buß, Florenz; Wilm, Lukas F. B.; Seidl, Michael; Podewitz, Maren; Dielmann, Fabian (2022-10-17). "Oxidative Fluorination of Selenium and Tellurium Compounds using a Thermally Stable Phosphonium SF5− Salt Accessible from SF6". Angewandte Chemie. 134 (42) e202209067. Bibcode:2022AngCh.13409067E. doi:10.1002/ange.202209067. ISSN 0044-8249.
  4. ↑ Chan, Julian M. W. (2019). "Pentafluorosulfanyl group: an emerging tool in optoelectronic materials". Journal of Materials Chemistry C. 7 (41): 12822–12834. doi:10.1039/C9TC01949A.
  5. 1 2 Röthel, Maike B.; Schöler, Andreas; Buß, Florenz; Löwe, Pawel; Dielmann, Fabian (2024-10-08). "Phosphonium SF5− Salts Derived from Sulfur Hexafluoride as Deoxyfluorination Reagents". Chemistry – A European Journal. 30 (56) e202402028. doi:10.1002/chem.202402028. ISSN 0947-6539. PMID 38958451.
  6. 1 2 3 Bittner, J.; Fuchs, J.; Seppelt, K. (February 1988). "Die Kristallstruktur des SF5− -Anions". Zeitschrift für anorganische und allgemeine Chemie. 557 (1): 182–190. Bibcode:1988ZAACh.557..182B. doi:10.1002/zaac.19885570119.
  7. 1 2 Jaeger, Ruben; Talavera, Maria; Braun, Thomas (July 2021). "Studies on the reactivity of Rh(I) complexes towards SF5Cl". Journal of Fluorine Chemistry. 247 109803. doi:10.1016/j.jfluchem.2021.109803.
  8. ↑ Clark, M.; Kellen-Yuen, C. J.; Robinson, K. D.; Zhang, H.; Yang, Z. Y.; Madappat, K. V.; Fuller, J. W.; Atwood, J. L.; Thrasher, J. S. (1992). "'Naked' SF5− anion: the crystal and molecular structure of [Cs+.(18-crown-6)2] [SF5-]". European Journal of Solid State and Inorganic Chemistry. 29 (4–5): 809–833.
  9. ↑ Matsumoto, Kazuhiko; Haruki, Yuki; Sawada, Shunsuke; Yamada, Shigeyuki; Konno, Tsutomu; Hagiwara, Rika (2018-12-03). "Stabilization of SF5– with Glyme-Coordinated Alkali Metal Cations". Inorganic Chemistry. 57 (23): 14882–14889. doi:10.1021/acs.inorgchem.8b02655. hdl:2433/245207. ISSN 0020-1669. PMID 30444364.