Carbon subsulfide

Chembox new
Name = 1,2-Propanediene-1,3-dithione
ImageFile =
ImageSize = 250px
ImageName = Carbon subsulfide
OtherNames = Carbon Subsulfide, Tricarbon Disulfide
Section1 = Chembox Identifiers
CASNo = 627-34-9
Section2 = Chembox Properties
Formula = C₃S₂
MolarMass = 100.162 g/mol
Appearance = red liquid
Density = 1.27
Solubility = insoluble in water
MeltingPt = -1°C
BoilingPt = 90°C
Section3 = Chembox Hazards
RPhrases =
SPhrases =

Carbon Subsulfide is the chemical compound with the formula C₃S₂. This deep red liquid is immiscible with water but soluble in organic solvents. It readily polymerizes at room temperature to form a hard black solid.

ynthesis and structure

C₃S₂ was discovered by Béla Lengyel, [cite journal
title = Ueber ein neues Kohlenstoffsulfid
journal = Berichte der deutschen chemischen Gesellschaft
volume = 26
year = 1893
pages = 2960-2968
author = B. von Lengyel
doi = 10.1002/cber.189302603124] who assigned it an unsymmetrical structure. Later, infrared and Raman spectroscopy showed that the structure is symmetrical with a D_∞h point group symmetry, [cite journal
title = Infrared and Raman Spectra of Carbon Subsulfide
journal = Journal of Chemical Physics
volume = 45
year = 1966
pages = 1788-1793
author = Smith, W. H., Leroi, G. E.
doi = 10.1063/1.1727828] i.e. S=C=C=C=S. This compound is analogous to carbon suboxide whose structure is O=C=C=C=O.

Lengyel first synthesized this compound by passing CS₂ vapor through an electric arc with carbon electrodes. This treatment produced a black solution that after filtration and evaporation gave a cherry-red liquid. He determined the molecular mass by cryoscopy. Later preparations of C₃S₂ include thermolysis of a stream of CS₂ in a quartz tube heated to 900 to 1100 ℃ as well as flash vacuum pyrolysis (FVP) of 1,2-dithiole-3-thiones. [cite journal
title = The formation of 1,2-propadiene-1,3-dithione from flash vacuum of 1,2-dithiole-3-thiones
journal = Tetrahedron Letters
volume = 27
year = 1996
pages = 4805-4808
author = Pedersen, C. T.
doi = 10.1016/0040-4039(96)00941-0]

Reactions and occurrence

Among its few known reactions, C₃S₂ can reacts with bromine to form the cyclic disulfide. [cite journal
title = The chemistry of carbon subsulfide
journal = Sulfur Reports
volume = 21
year = 1999
pages = 423-445
author = Stadlbauer, W., Kappe, T.] :

C₃S₂ polymerizes under applied pressure to give a black semi-conducting solid. A similar pressure-induced polymerization of CS₂ also gives a black semiconducting polymer.

In addition, reactions of C₃S₂ can yield highly condensed sulfur-containing compound, e.g. the reaction of C₃S₂ with 2-aminopyridine:

Using microwave spectroscopy, small C_nS₂ clusters have been detected in interstellar medium. [cite journal
title = Sulfur in IRC+10216
journal = Astronomy and Astrophysics
volume = 181
year = 1987
pages = L9-L12
author = Cernicharo, J., Guelin, M., Hein, H., Kahane, C.] The rotational transitions of these small carbon sulfides molecules matched with the corresponding molecules.

References