Sulfur chloride pentafluoride

Sulfur chloride pentafluoride is an inorganic compound with the formula SF₅Cl. It exists as a colorless gas at room temperature and is highly toxic, like most inorganic compounds containing the pentafluorosulfide (–SF₅) functional group.^[1] The compound adopts an octahedral geometry with C
_4v symmetry. Sulfur chloride pentafluoride is the only commercially available reagent for adding the –SF₅ group to organic compounds.^[2][3]

Sulfur chloride pentafluoride

Names
Other names Pentafluorochlorosulfanyl
Identifiers
CAS Number	13780-57-9 N
3D model (JSmol)	Interactive image
ChemSpider	109933 Y
ECHA InfoCard	100.034.014
PubChem CID	123330
UNII	T36C2GHD3T Y
CompTox Dashboard (EPA)	DTXSID60160316
InChI InChI=1S/ClF5S/c1-7(2,3,4,5)6 Y Key: GSYNTTDHMKSMFY-UHFFFAOYSA-N Y
SMILES ClS(F)(F)(F)(F)F
Properties
Chemical formula	SF5Cl
Molar mass	162.510 g/mol
Appearance	Colorless gas
Density	6.642 g/dm3
Melting point	−64 °C (−83 °F; 209 K)
Boiling point	−19 °C (−2 °F; 254 K)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Toxic
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N (what is YN ?) Infobox references

Reactivity

SF₅Cl is highly reactive and toxic. In contrast, sulfur hexafluoride (SF₆) is inert and nontoxic despite having a closely related chemical formula. This difference highlights the lability of the S–Cl bond in SF₅Cl.

Under free-radical conditions, SF₅Cl adds across double bonds. The following reaction occurs with propene:

CH
₃CH=CH
₂ + SF
₅Cl → CH₃CHClCH₂SF₅

The addition reaction is catalyzed by (CH₃CH₂)₃B at around −30 °C. SF₅Br is used similarly.^[2]

SF₅Cl is also a precursor to O(SF₅)₂ and F₂NSF₅ (from tetrafluorohydrazine).

Synthesis

Sulfur chloropentafluoride can be synthesized by several routes, starting from two lower sulfur fluorides, sulfur tetrafluoride and disulfur decafluoride:^[1]

SF₄ + Cl₂ + CsF → SF₅Cl + CsCl

ClF + SF₄ → SF₅Cl

S₂F₁₀ + Cl₂ → 2 SF₅Cl

The corresponding SF
₅Br is prepared similarly from in-situ generated bromine monofluoride.^[4]