Disulfur dichloride
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| Disulfur dichloride | |
|---|---|
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| General | |
| Systematic name | Sulfur(I) chloride |
| Other names | Disulfur dichloride Sulfur monochloride |
| Molecular formula | S2Cl2 |
| SMILES | ClSSCl |
| Molar mass | 135.04 g/mol |
| Appearance | colorless liquid |
| CAS number | [10025-67-9] |
| Properties | |
| Density and phase | 1.688 g/cm3, liquid |
| Solubility in water | decomp with loss of HCl |
| Other solvents | benzene, chlorocarbons |
| Melting point | –80 °C |
| Boiling point | 137.1 °C |
| Structure | |
| Coordination geometry |
gauche |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | corrosive |
| NFPA 704 |
1
2
1
|
| R/S statement | R: 14-20-25-29-35-50 S: 26-36/37/39-45-61 |
| RTECS number | WS4300000 |
| Supplementary data page | |
| Structure and properties |
n = 1.658 |
| Thermodynamic data |
Phase behaviour liquid |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related compounds | SCl2 SO2Cl2 SF4 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Disulfur dichloride is S2Cl2. An alternative name for this compound is sulfur monochloride, the name implied by its empirical formula, SCl. S2Cl2 has the structure implied by the formula Cl-S-S-Cl, wherein the angle between the Cla-S-S and S-S-Clb planes is 90°. This structure is referred to as gauche, and is akin to that for H2O2. A different isomer of S2Cl2 is S=SCl2; this isomer forms transiently when S2Cl2 is exposed to UV-radiation.
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[edit] Synthesis
S2Cl2 forms by limited chlorination of elemental sulfur:
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- S8 + 4 Cl2 → 4 S2Cl2 ΔH = −58.2 kJ/mol
- S2Cl2 + Cl2 → 2 SCl2 ΔH = −40.6 kJ/mol
As indicated above, excess Cl2 converts the S2Cl2 into SCl2. Both reactions are reversible. S2Cl2 also arises from the chlorination of CS2 as in the synthesis of thiophosgene.
[edit] Properties
Pure disulfur dichloride is colorless, but impure samples are often yellow. It decomposes upon standing and smokes in wet air due to reaction with water
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- 2 S2Cl2 + 2 H2O → SO2 + 4 HCl + 3/8 S8
[edit] Applications in synthesis
S2Cl2 has been used to introduce C-S bonds. In the presence of AlCl3, S2Cl2 reacts with benzene to give diphenyl sulfide:
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- S2Cl2 + C6H6 → (C6H5)2S + 2 HCl + 1/8 S8
Anilines react with S2Cl2 in the presence of NaOH via the so-called Herz reaction to give ortho-aminothiophenolates. These species are precursors to thioindigo dyes. It is also used to prepare the sulfur mustard "gas" by reaction with ethylene:
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- S2Cl2 + 2 C2H4 → (ClC2H4)2S + 1/8 S8
[edit] References
- Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- W. W. Hartman, L. A. Smith, and J. B. Dickey "Diphenylsulfide" Organic Syntheses, Coll. Vol. 2, p.242; Vol. 14, p.36.
- R. J. Cremlyn “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). ISBN 0-471-95512-4
- Garcia-Valverde M., Torroba T. (2006). "Heterocyclic chemistry of sulfur chlorides - Fast ways to complex heterocycles". European J. Org. Chem. 4: 849-861.
