Carbonyl sulfide
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| Carbonyl sulfide | |
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| Chemical name | carbonyl sulfide |
| Chemical formula | OCS |
| InChI | InChI=1/COS/c2-1-3 |
| Molecular mass | 60.07 g mol−1 |
| Melting point | −139 °C |
| Boiling point | −50 °C |
| Density | 0.00251 g cm−3 |
| CAS number | 463-58-1 |
| SMILES | O=C=S |
| NFPA 704 |
4
3
0
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| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Carbonyl sulfide is a colourless gas at room temperature with an unpleasant odor. The chemical formula is OCS or COS and the molecule consists of a carbonyl group with the carbon atom also double bonded to a sulfur atom. Carbonyl sulfide can be considered to be a hybrid of carbon dioxide and carbon disulfide.
Carbonyl sulfide is the major sulfur compound naturally present in the atmosphere at 0.5 (± 0.05) ppb and is an important part of the global sulfur cycle. It is also present in foodstuffs such as cheese and prepared vegetables of the cabbage family. OCS is naturally present in grains and seeds in the range of 0.05-0.1 mg kg−1.
Carbonyl sulfide is a component of volcanic gases and gases emitted by deep sea vents. 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.[1] Carbonyl sulfide forms in the atmosphere as a result of sulfur emissions. In one study the tracking of carbonyl sulfide in Antarctica ice cores gives a detailed picture of OCS concentrations from 1640 to the present day separating anthropogenic and non-anthropogenic sulfur sources. Carbonyl sulfide is transported into the stratospheric sulfate layer where it is oxidized to sulfuric acid.
Carbonyl sulfide is a potential fumigant and a replacement for methyl bromide and phosphine. Carbonyl sulfide is also an interstellar molecule.
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[edit] Synthesis
KCNS + H2SO4 H2O → KHSO4 + NH4HSO4 + COS
The laboratory synthesis starts from potassium thiocyanate and sulfuric acid. The gas contains significant amounts of byproducts and has to be purified. [2]
[edit] References
- ^ Luke Leman, Leslie Orgel, M. Reza Ghadiri (2004). "Carbonyl Sulfide–Mediated Prebiotic Formation of Peptides". Science 306 (5694): 283 - 286. DOI:10.1126/science.1102722.
- ^ Ferm R. J. (1957). "The Chemistry of Carbonyl sulfide". Chemical Reviews 57 (4): 621-640. DOI:10.1021/cr50016a002.
[edit] Further reading
- Beck, M. T. and Kauffman, G. B. (1985). "COS and C3S2: The Discovery and Chemistry of Two Important Inorganic Sulfur Compounds". Polyhedron 4 (5): 775-781. DOI:10.1016/S0277-5387(00)87025-4.
- Crutzen, P. (1976). "The possible importance of COS for the sulfate layer of the stratosphere". Geophys. Res. Lett. 3: 73–76.
- Svoronos P. D. N., Bruno T. J. (2002). "Carbonyl sulfide: A review of its chemistry and properties". Industrial & Engineering Chemistry Research 41 (22): 5321-5336. DOI:10.1021/ie020365n.
