| methodical name | Sulfur(IV) fluoride |
| other names | Sulfur tetrafluoride |
| molecule formula | SF4 |
| Molar mass | 108.07 g/mol |
| Appearance | colorless gas |
| CAS number | <7783-60-0> |
| Density and also phase | 1.95 g cm−3, −78 °C |
| Solubility in water | decomp |
| other solvents | benzene |
| melting point | −121.0 °C |
| boiling point | −38 °C |
| Moleculargeometry | Seesaw |
| Coordinationgeometry | C2v |
| Dipole moment | 0.632 D<1> |
| MSDS | exterior MSDS |
| key hazards | extremely toxiccorrosive |
| NFPA 704 | Sulfur tetrafluoride is the chemical compound through the formula SF4. This types exists as a gas at standard conditions. That is a corrosive species that releases dangerous HF ~ above exposure to water or moisture. Regardless of these unwelcome characteristics, this compound is a beneficial reagent because that the preparation of organofluorine compounds,<2> some of which are necessary in the pharmaceutical and also specialty chemistry industries. As well as SF4, two other "binary" sulfur fluorides are well known, SF6 and S2F10. Additional encourage knowledge day-to-day Sensitivity check  safe Weighing variety Ensures exact Results  8 actions to a Clean Balance – and also 5 services to save It Clean Contents |
structure of the SF4 molecule
Sulfur in SF4 is in the formal 4+ oxidation state. The sulfur"s complete of six valence electrons, two type a "lone pair." The structure of SF4 can thus be anticipated making use of the ethics of VSEPR theory: that is a trigonal bipyramid, with S in ~ the center. One of the three equatorial location is populated by a nonbonding lone pair of electrons. Skipping this lone pair, SF4 resembles a "see-saw." Consequently, the molecule has two distinct types of F ligands, two axial and also two equatorial. The relevant bond distances are S-Fax = 1.643 Å and S-Feq = 1.542 Å. It is usual for the axial ligands in hypervalent molecule to it is in bonded less strongly. In comparison to SF4, the connected molecule SF6 has sulfur in the 6+ state, no valence electrons continue to be nonbonding top top sulfur, therefore the molecule through a very symmetrical octahedral structure. More contrasting v SF4, SF6 is extremely inert chemically.
The 19F NMR spectrum that SF4 reveals just one signal, which shows that the axial and equatorial F atom positions swiftly interconvert via "pseudorotation."<3>
Synthesis and manufacture
SF4 is created by the reaction that SCl2, Cl2, and also NaF:
SCl2 + Cl2 + 4NaF → SF4 + 4NaClInterestingly, treatment of SCl2 with NaF also affords SF4, no SF2. SF2 is unstable, the condenses with itself to type SF4 and also SSF2.
usage of SF4 for the synthetic of fluorocarbons
In organic synthesis, SF4 is offered to convert COH and C=O teams into CF and also CF2 groups, respectively.<4> details alcohols readily offer the matching fluorocarbon. Ketones and also aldehydes offer geminal difluorides. The visibility of proton alpha come the carbonyl leads to side reactions and also diminished (30- 40%) yield. Additionally diols can give cyclic sulfite esters, (RO)2SO. Carboxylic acids transform to trifluoromethyl derivatives. For example treatment the heptanoic acid through SF4 at 100-130 °C produce 1,1,1-trifluoroheptane. The coproducts from these fluorinations, including unreacted SF4 in addition to SOF2 and SO2, space toxic however can it is in neutralized by your treatment with aqueous KOH.
The use of SF4 is gift superseded in recent years by the more conveniently handled diethylaminosulfur trifluoride, Et2NSF3, "DAST," where Et = CH3CH2.
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<5> This reagent is prepared from SF4:<6>