Sulfur tetrachloride

Sulfur tetrachloride

Names
IUPAC name Sulfur(IV) chloride
Identifiers
CAS Number	13451-08-6
3D model (Jmol)	Interactive image
ECHA InfoCard	100.149.178
InChI InChI=1/Cl4S/c1-5(2,3)4
SMILES ClS(Cl)(Cl)Cl
Properties
Chemical formula	SCl4
Molar mass	173.87
Appearance	White powder
Melting point	−31 °C (−24 °F; 242 K)
Boiling point	−20 °C (−4 °F; 253 K) (decomposes)
Solubility in water	soluble in water
Hazards
R-phrases	R14, R34, R50
S-phrases	(S1/2), S26, S45, S61
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sulfur tetrachloride is an inorganic compound with chemical formula SCl₄. It has only been obtained as an unstable pale yellow solid. The corresponding SF₄ is a stable, useful reagent.

Preparation and structure

It is obtained by treating sulfur dichloride with chlorine at 193 K:

${\displaystyle {\begin{matrix}{}\\{\ce {{SCl2}+Cl2->[{\ce {193~K}}]SCl4}}\\{}\end{matrix}}}$

(1)

It melts with simultaneous decomposition above −20 °C.^[1]

Its solid structure is uncertain. It is probably the salt SCl₃⁺Cl⁻, since related salts are known with noncoordinating anions.^[2][3] In contrast to this tetrachloride, SF₄ is a neutral molecule.^[4]

Reactions

It decomposes above −30 °C to sulfur dichloride and chlorine at temperatures above 242 K:

${\displaystyle {\begin{matrix}{}\\{\ce {SCl4->[{\ce {-15~^{\circ }C}}]{SCl2}+Cl2}}\\{}\end{matrix}}}$

(2)

It hydrolyzes readily:

${\displaystyle {\ce {{SCl4}+H2O->{SOCl2}+{2HCl}}}}$

(3)

Sulfur tetrachloride reacts with water, producing hydrogen chloride and sulfur dioxide through the hydrolysis process. Thionyl chloride is an implied intermediate.^[5]

${\displaystyle {\ce {{SCl4}+2H2O->{SO2}+{4HCl}}}}$

(4)

• Oxidized by nitric acid:

${\displaystyle {\ce {{SCl4}+{2HNO3}+2H2O->{H2SO4}+2NO2{\uparrow }+{4HCl}}}}$

(5)

References

1. Georg Brauer: Handbuch der Präparativen Anorganischen Chemie. (German)
2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
3. Christian, Beverly H.; Collins, Michael J.; Gillespie, Ronald J.; Sawyer, Jeffery F. "Preparations, Raman spectra, and crystal structures of (SCl₃)(SbCl₆), (SeCl₃)(SbCl₆), (SBr_1.2Cl_1.8)(SbCl⁶), (TeCl₃)(AlCl₄) (triclinic modification), (TeCl₃)(SbF₆), (TeCl₃)(AsF₆), and (TeF₃)₂(SO₄)" Inorganic Chemistry 1986, volume 25, 777-88. doi:10.1021/ic00226a012
4. Goettel, J. T., Kostiuk, N. and Gerken, M. (2013), The Solid-State Structure of SF₄: The Final Piece of the Puzzle . Angew. Chem. Int. Ed., 52: 8037–8040. doi:10.1002/anie.201302917
5. Holleman-Wiberg, Lehrbuch der Anorganischen Chemie, 101. Auflage, de Gruyter Verlag 1995 ISBN 3-11-012641-9 (German)