Disulfur dichloride

Disulfur dichloride
IUPAC name Disulfur dichloride
Systematic name Dichlorodisulfane
Other names Bis[chloridosulfur](S–S) Dimeric sulfenic chloride Sulfur monochloride
Identifiers
CAS number	10025-67-9 Y, 85408-26-0 (isobutenate)
PubChem	24807 Y, 174464 (isobutenate) Y
ChemSpider	23192 Y, 152167 (isobutenate) Y
EC number	233-036-2
UN number	3390
MeSH	Sulfur+monochloride
RTECS number	WS4300000
Jmol-3D images	Image 1
SMILES ClSSCl
InChI InChI=1S/Cl2S2/c1-3-4-2 Y Key: PXJJSXABGXMUSU-UHFFFAOYSA-N Y InChI=1/Cl2S2/c1-3-4-2 Key: PXJJSXABGXMUSU-UHFFFAOYAK
Properties
Molecular formula	S2Cl2
Molar mass	135.04 g/mol
Appearance	yellow liquid
Density	1.688 g/cm3
Melting point	-80 °C, 193 K, -112 °F
Boiling point	137.1 °C, 410 K, 279 °F
Solubility in water	decomp with loss of HCl
Solubility	soluble in ethanol, benzene, ether, chloroform, CCl4 [1]
Refractive index (nD)	1.658
Structure
Coordination geometry	gauche
Dipole moment	1.60 D [1]
Hazards
MSDS	ICSC 0958
EU Index	016-012-00-4
EU classification	Toxic (T) Harmful (Xn) Corrosive (C) Dangerous for the environment (N)
R-phrases	R14, R20, R25, R29, R35, R50
S-phrases	(S1/2), S26, S36/37/39, S45, S61
NFPA 704	1 2 1
Flash point	118.5 °C
Autoignition temperature	234 °C
Related compounds
Related sulfur chlorides	Sulfur dichloride Thionyl chloride Sulfuryl chloride
Related compounds	Disulfur difluoride Disulfur dibromide
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Disulfur dichloride is the chemical compound with the formula S₂Cl₂ ^{[2][3][4] [5]} . Some alternative names for this compound are sulfur monochloride (the name implied by its empirical formula, SCl), disulphur dichloride (British English Spelling) and sulphur monochloride (British English Spelling). S₂Cl₂ has the structure implied by the formula Cl-S-S-Cl, wherein the angle between the Cl^a-S-S and S-S-Cl^b 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 (see thiosulfoxides).

Synthesis and basic properties

Disulfur dichloride is an orange/yellow liquid that smokes in air due to reaction with water:

2 S₂Cl₂ + 2 H₂O → SO₂ + 4 HCl + 3/8 S₈

It is synthesized by partial chlorination of elemental sulfur:

S₈ + 4 Cl₂ → 4 S₂Cl₂ ΔH = −58.2 kJ/mol

Excess chlorine gives sulfur dichloride:

S₂Cl₂ + Cl₂ → 2 SCl₂ ΔH = −40.6 kJ/mol

Both reactions are reversible, and upon standing, SCl₂ releases chlorine to revert to the disulfur dichloride. It has the ability to dissolve sulfur, which reflects in part the formation of polysulfanes:

S₂Cl₂ + n S → S_2+nCl₂

S₂Cl₂ also arises from the chlorination of CS₂ as in the synthesis of thiophosgene.

Applications

S₂Cl₂ has been used to introduce C-S bonds. In the presence of AlCl₃, S₂Cl₂ reacts with benzene to give diphenyl sulfide:

S₂Cl₂ + 2 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:

S₂Cl₂ + 2 C₂H₄ → (ClC₂H₄)₂S + 1/8 S₈

Other uses include manufacturing sulfur dyes, insecticides, synthetic rubbers. Also used in cold vulcanization of rubbers, as polymerization catalyst for vegetable oils and for hardening soft woods.

References

1. ^ ^{a b} Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
2. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
3. ^ Hartman, W. W.; Smith, L. A.; Dickey, J. B. (1934), "Diphenylsulfide", Org. Synth. 14: 36, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv2p0242 ; Coll. Vol. 2: 242 
4. ^ R. J. Cremlyn “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). ISBN 0-471-95512-4
5. ^ Garcia-Valverde M., Torroba T. (2006). "Heterocyclic chemistry of sulfur chlorides - Fast ways to complex heterocycles". European J. Org. Chem. 4 (4): 849–861. doi:10.1002/ejoc.200500786.