Carbon monosulfide

{{About-distinguish2|an unstable molecule|CS gas, a tear gas, nor caesium, an element with symbol Cs}}

{{Chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 427865018

| ImageFileL1 = Carbon monosulfide.svg

| ImageSizeL1 = 120

| ImageAltL1 = Lewis structure, showing a C–S bond distance of 1.5349 angstroms

| ImageFileR1 = Carbon monosulfide molecule spacefill.png

| ImageSizeR1 = 120

| ImageAltR1 = Space-filling model of the carbon monosulfide molecule

| IUPACName = carbon monosulfide

| PIN =

| OtherNames = carbon(II) sulfide, thiocarbonyl, sulfidocarbon, methanidylidynesulfanium

|Section1={{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|??}}

| CASNo = 2944-05-0

| PubChem = 108054

| Beilstein = 1697516, 1918616

| ChEBI = 30253

| Gmelin = 648

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 97157

| SMILES = [S+]#[C-]

| InChI = 1/CS/c1-2

| InChIKey = DXHPZXWIPWDXHJ-UHFFFAOYAW

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/CS/c1-2

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = DXHPZXWIPWDXHJ-UHFFFAOYSA-N}}

|Section2={{Chembox Properties

| C=1 | S=1

| Appearance = reddish crystalline powder

| Density =

| MeltingPt =

| BoilingPt =

| Solubility = insoluble

}}

|Section3={{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt =}}

| Section9 = {{Chembox Related

| OtherAnions = Carbon monoxide

| OtherCations = Silicon monosulfide
Germanium monosulfide
Tin(II) sulfide
Lead(II) sulfide

| OtherFunction =

| OtherFunction_label =

| OtherCompounds =

}}

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Carbon monosulfide is a chemical compound with the formula CS. This diatomic molecule is the sulfur analogue of carbon monoxide, and is unstable as a solid or a liquid, but it has been observed as a gas both in the laboratory and in the interstellar medium.{{cite journal |author1=Wilson, R. W. |author2=Penzias, A. A. |author3=Wannier, P. G. |author4=Linke, R. A. |title= Isotopic abundances in interstellar carbon monosulfide |journal= Astrophysical Journal |year= 1976 |volume= 204 |issue= pt 2 |pages= L135–L137 |doi= 10.1086/182072 |bibcode= 1976ApJ...204L.135W |doi-access= free }} The molecule resembles carbon monoxide with a triple bond between carbon and sulfur. The molecule is not intrinsically unstable, but it tends to polymerize in sunlight to a brown mass, as first discovered in 1868 and 1872.{{multiref2|1=Discovery in 1868: Loew, Oscar (1868). "{{lang|de|Notiz über die Wirkung des Sonnenlichts auf Kohlenbisulfid}}", from Zeitschrift für Chemie, vol. 11 issue 4, p. [https://www.digitale-sammlungen.de/de/view/bsb11039731?page=632,633 622] — via the Munich Digitization Center.|2=History and subsequent elucidation of the polymer: Dewar, James; Owen Jones, Humphrey (1910). "Note on carbon monosulphide", from Proceedings of the Royal Society of London, Series A, volume 83 issue 564, pp. 408–413. {{doi|10.1098/rspa.1910.0029}}}} The polymer is quite stable, decomposing a little at 360 °C to carbon disulfide. This tendency towards polymerization reflects the greater stability of C–S single bonds.

Polymers with the formula (CS)_n have been reported,{{cite journal |author1=Chou, J.-H. |author2=Rauchfuss, T. B. |title= Solvatothermal Routes to Poly(Carbon Monosulfide)s Using Kinetically Stabilized Precursors |journal= Journal of the American Chemical Society |year= 1997 |volume= 119 |issue= 19 |pages= 4537–4538 |doi= 10.1021/ja970042w |url= http://faculty.scs.illinois.edu/rauchfus/refs/polyCS.pdf }} and the formal dimer is ethenedithione. Also, CS has been observed as a ligand in some transition metal complexes.{{Citation needed|date=August 2024}}

The simplest carbon monosulfide synthesis decomposes carbon disulfide in a high-voltage AC arc.Moltzen, Ejner K.; Klabunde, Kenneth J.; and Senning, Alexander (1988). "Carbon monosulfide", from Chemical Reviews, vol. 88 issue 2, pp. 391-406. {{doi|10.1021/cr00084a003}}.