Carbon diselenide

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Carbon diselenide
Carbon diselenide.png
Carbon-diselenide-3D-balls.png
Carbon-diselenide-3D-vdW.png
Names
Other names
Carbon selenide, diselenoxomethane, methanediselone
Identifiers
506-80-9 YesY
ChemSpider 61481 N
Jmol 3D model Interactive image
PubChem 68174
  • InChI=1S/CSe2/c2-1-3 N
    Key: JNZSJDBNBJWXMZ-UHFFFAOYSA-N N
  • InChI=1/CSe2/c2-1-3
    Key: JNZSJDBNBJWXMZ-UHFFFAOYAM
  • [Se]=C=[Se]
Properties
CSe2
Molar mass 169.93 g/mol
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
5032 J/mol K
263.2 J/mol K
219.2 kJ/mol
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
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 an analogue of carbon disulfide (CS2). 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 –[Se–C(=Se)–C(=Se)–Se]–.[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 Et2NH + CSe2 → (Et2NH2+)(Et2NCSe2)

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]

Mixed with air, carbon diselenide (CSe2) releases an extremely offensive odor.[6] Its smell forced an evacuation of a nearby village when it was first synthesized in 1936. The stench can be neutralized by oxidizing with bleach.[7] Because of the odor, synthetic pathways have been developed to avoid its use.[8]

References

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  8. US patent 4462938, Wudl, F., "Process for producing chalcogen containing compounds", issued 1984-07-31, assigned to AT&T Bell Laboratories .