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Carbon diselenide
Names
	IUPAC name Carbon diselenide
	Systematic IUPAC name Methanediselenone
	Other names Carbon selenide; Diselenoxomethane; Methanediselone; Carbon(IV) selenide
Identifiers
CAS Number	506-80-9 ;
3D model (JSmol)	Interactive image;
ChemSpider	61481 ;
ECHA InfoCard	100.007.323
EC Number	208-054-9;
PubChem CID	68174;
UNII	WD123H448C ;
CompTox Dashboard (EPA)	DTXSID1060138 ;
	InChI InChI=1S/CSe2/c2-1-3 Key: JNZSJDBNBJWXMZ-UHFFFAOYSA-N ; InChI=1/CSe2/c2-1-3 Key: JNZSJDBNBJWXMZ-UHFFFAOYAM;
	SMILES [Se]=C=[Se];
Properties
Chemical formula	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)
Solubility in water	0.054 g/(100 mL)
Solubility	Soluble in CS2, toluene
Dipole moment	0 D
Thermochemistry
Heat capacity (C)	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). verify (what is ?) Infobox references

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

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

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

^ ^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 .