Carbon diselenide
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| Names | |
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| IUPAC name
Carbon diselenide
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| Systematic IUPAC name
Methanediselenone | |
| Other names
Carbon selenide
Diselenoxomethane Methanediselone Carbon(IV) selenide | |
| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.007.323 |
| EC Number |
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PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| CSe2 | |
| Molar mass | 169.953 g·mol−1 |
| Appearance | Yellow liquid |
| Density | 2.6824 g/cm3 |
| Melting point | −43.7 °C (−46.7 °F; 229.5 K) |
| Boiling point | 125.5 °C (257.9 °F; 398.6 K) |
| 0.054 g/(100 mL) | |
| Solubility | Soluble in CS2, toluene |
| 0 D | |
| Thermochemistry | |
Heat capacity (C)
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50.32 J/(mol·K) (gas) |
Std molar
entropy (S⦵298) |
263.2 J/(mol·K) (gas) |
Std enthalpy of
formation (ΔfH⦵298) |
219.2 kJ/mol (liquid) |
| Hazards | |
| Flash point | 30 °C (86 °F; 303 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Carbon diselenide is an inorganic compound with the chemical formula CSe2. It is a yellow-orange oily liquid with pungent odor. It is the selenium analogue of carbon disulfide (CS2) and carbon dioxide (CO2). This light-sensitive compound is insoluble in water and soluble in organic solvents.
Synthesis, structure and reactions
[edit]Carbon diselenide is a linear molecule with D∞h symmetry. It is produced by reacting selenium powder with dichloromethane vapor near 550 °C.[1]
- 2 Se + CH2Cl2 → CSe2 + 2 HCl
It was first reported by Grimm and Metzger, who prepared it by treating hydrogen selenide with carbon tetrachloride in a hot tube.[2]
Like carbon disulfide, carbon diselenide polymerizes under high pressure. The structure of the polymer is thought to be a head-to-head structure with a backbone in the form of [−C(=Se)−Se−]n.[3] The polymer is a semiconductor with a room-temperature conductivity of 50 S/cm.
In addition, carbon diselenide is a precursor to tetraselenafulvalenes,[4] the selenium analogue of tetrathiafulvalene, which can be further used to synthesize organic conductors and organic superconductors.
Carbon diselenide reacts with secondary amines to give dialkydiselenocarbamates:[1]
- 2 (CH3CH2)2NH + CSe2 → [(CH3CH2)2NH+2]((CH3CH2)2N−CSe−2)
Safety
[edit]Carbon diselenide has high vapor pressure. It has a moderate toxicity and presents an inhalation hazard. It may be dangerous due to its easy membrane transport. It decomposes slowly in storage (about 1% per month at –30 °C). When obtained commercially, its cost is high.[5]
Pure distilled carbon diselenide has an odor very similar to that of carbon disulfide, but mixed with air, it creates extremely offensive odors (corresponding to new, highly toxic reaction products).[6][7] Its smell forced an evacuation of a nearby village when it was first synthesized in 1936.[7] Because of the odor, synthetic pathways have been developed to avoid its use.[8]
References
[edit]- ^ a b Pan, W.-H.; Fackler, J. P. Jr.; Anderson, D. M.; Henderson, S. G. D.; Stephenson, T. A. (1982). "2. Diselenocarbamates from Carbon Diselenide". In Fackler, J. P. Jr. (ed.). Inorganic Syntheses. Vol. 21. pp. 6–11. doi:10.1002/9780470132524.ch2. ISBN 978-0-470-13252-4.
- ^ Grimm, H. G.; Metzger, H. (1936). "Über Darstellung und Eigenschaften des Selenkohlenstoffs". Berichte der Deutschen Chemischen Gesellschaft (A and B Series). 69 (6): 1356–1364. doi:10.1002/cber.19360690626.
- ^ Carraher, C. E. Jr.; Pittman, C. U. Jr. (2005). "Poly(Carbon Disulfide), Poly(Carbon Diselenide), and Polythiocyanogen". Inorganic Polymers. 21. doi:10.1002/14356007.a14_241. ISBN 3-527-30673-0.
- ^ Engler, E. M.; Patel, V. V. (1974). "Structure control in organic metals. Synthesis of tetraselenofulvalene and its charge transfer salt with tetracyano-p-quinodimethane". Journal of the American Chemical Society. 96 (23): 7376–7378. doi:10.1021/ja00810a042. PMID 4814748.
- ^ "Carbon Diselenide CSe2". Cse2.com. Retrieved 2012-04-04.
- ^ Wolfgang H. H. Gunther. Organic Selenium Compounds: Their Chemistry and Biology.
carbon diselenide has by far the worst odor this author has experienced in his lifetime of working with selenium compounds
- ^ a b Lowe, Derek (2005-03-03). "Things I Won't Work With: Carbon Diselenide". In the Pipeline. Science. Archived from the original on 23 September 2015. Retrieved 20 November 2015.
- ^ US patent 4462938, Wudl, F., "Process for producing chalcogen containing compounds", issued 1984-07-31, assigned to AT&T Bell Laboratories.