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Carbonyl sulfide

Carbonyl sulfide
Carbonyl sulfide
Space-filling 3D model of carbonyl sulfide
Names
IUPAC name
Carbon oxide sulfide
Identifiers
463-58-1 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:16573 YesY
ChemSpider 9644 YesY
ECHA InfoCard 100.006.674
EC Number 207-340-0
KEGG C07331 YesY
PubChem 10039
Properties
COS
Molar mass 60.075 g/mol
Appearance colorless gas
Odor sulfide-like
Density 2.51 g/L
Melting point −138.8 °C (−217.8 °F; 134.3 K)
Boiling point −50.2 °C (−58.4 °F; 223.0 K)
0.376 g/100 mL (0 °C)
0.125 g/100 mL (25 °C)
Solubility very soluble in KOH, CS2
soluble in alcohol, toluene
-32.4·10−6 cm3/mol
0.65 D
Thermochemistry
41.5 J/mol K
231.5 J/mol K
-141.8 kJ/mol
Hazards
Safety data sheet Carbonyl sulfide MSDS
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Explosive limits 12-29%
Related compounds
Related compounds
 Carbon dioxide
Carbon disulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Carbonyl sulfide is the organic compound with the formula OCS. Commonly written as COS, it is a colourless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl group double bonded to a sulfur atom. Carbonyl sulfide can be considered to be intermediate between carbon dioxide and carbon disulfide, both of which are valence isoelectronic with it.

Carbonyl sulfide decomposes in the presence of humidity and bases to carbon dioxide and hydrogen sulfide.

This compound is found to catalyze the formation of peptides from amino acids. This finding is an extension of the Miller–Urey experiment and it is suggested that carbonyl sulfide played a significant role in the origin of life.

Carbonyl sulfide is the most abundant sulfur compound naturally present in the atmosphere, at 0.5±0.05 ppb, because it is emitted from oceans, volcanoes and deep sea vents. As such, it is a significant compound in the global sulfur cycle. Measurements on the Antarctica ice cores and from air trapped in snow above glaciers (firn air) have provided a detailed picture of OCS concentrations from 1640 to the present day and allow an understanding of the relative importance of anthropogenic and non-anthropogenic sources of this gas to the atmosphere. Some carbonyl sulfide that is transported into the stratospheric sulfate layer is oxidized to sulfuric acid. Sulfuric acid forms particulate which affects energy balance due to light scattering. The long atmospheric lifetime of COS makes it the major source of stratospheric sulfate, though sulfur dioxide from volcanic activity can be significant too. Carbonyl sulfide is also removed from the atmosphere by terrestrial vegetation by enzymes associated with the uptake of carbon dioxide during photosynthesis, and by hydrolysis in ocean waters. Loss processes, such as these, limit the persistence (or lifetime) of a molecule of COS in the atmosphere to a few years.


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