![]() 20–86 ☌) alternative to the chlorinative process above uses liquid bromine (Br 2) as oxidant and solvent: S(s) + 2 Br 2(l excess) + 4KF(s) → SF 4↑ + 4 KBr(brom) Use of SF 4 for the synthesis of fluorocarbons Moreover, sulfur dichloride may be replaced by elemental sulfur (S) and chlorine (Cl 2). Intramolecular dynamic equilibration of SF 4.Īt the laboratory scale, fluorination of elemental sulfur with cobaltic fluoride suffices: S + 4CoF 3 → SF 4 + 4CoF 2įor larger-scale syntheses, SF 4 is produced by the reaction of SCl 2 and NaF in acetonitrile: 3 SCl 2 + 4 NaF → SF 4 + S 2Cl 2 + 4 NaClĪt higher temperatures (e.g. The 19F NMR spectrum of SF 4 reveals only one signal, which indicates that the axial and equatorial F atom positions rapidly interconvert via pseudorotation. Further contrasting with SF 4, SF 6 is extraordinarily inert chemically. ![]() In contrast to SF 4, the related molecule SF 6 has sulfur in the 6+ state, no valence electrons remain nonbonding on sulfur, hence the molecule adopts a highly symmetrical octahedral structure. It is typical for the axial ligands in hypervalent molecules to be bonded less strongly. The relevant bond distances are S–F ax = 164.3 pm and S–F eq = 154.2 pm. Consequently, the molecule has two distinct types of F ligands, two axial and two equatorial. One of the three equatorial positions is occupied by a nonbonding lone pair of electrons. The structure of SF 4 can therefore be anticipated using the principles of VSEPR theory: it is a see-saw shape, with S at the center. Of sulfur's total of six valence electrons, two form a lone pair. Sulfur in SF 4 is in the formal +4 oxidation state. Despite these unwelcome characteristics, this compound is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries. ![]() It is a colorless corrosive gas that releases dangerous HF upon exposure to water or moisture. Sulfur tetrafluoride is the chemical compound with the formula S F 4.
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