Carbon diselenide is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemis ...

with the chemical formula CSe₂. It is a yellow-orange oily liquid with pungent odor. It is the

selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...

analogue of

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical n ...

(CS₂) and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

(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 Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definiti ...

. It is produced by reacting

powder with

dichloromethane Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour is widely used as a solvent. Although it is not miscible wit ...

vapor near 550 °C. :2 Se + CH₂Cl₂ → CSe₂ + 2 HCl It was first reported by Grimm and Metzger, who prepared it by treating

hydrogen selenide Hydrogen selenide is an inorganic compound with the formula H2Se. This hydrogen chalcogenide is the simplest and most commonly encountered hydride of selenium. H2Se is a colorless, flammable gas under standard conditions. It is the most toxic sel ...

with

carbon tetrachloride Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVACR) is an organic compound with the chemi ...

in a hot tube. Like

, 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 – e–C(=Se)–C(=Se)–Se��. The polymer is a

semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way ...

with a room-temperature conductivity of 50 S/cm. In addition, carbon diselenide is a precursor to tetraselenafulvalenes, the selenium analogue of

tetrathiafulvalene Tetrathiafulvalene is an organosulfur compound with the formula (. Studies on this heterocyclic compound contributed to the development of molecular electronics. TTF is related to the hydrocarbon fulvalene, , by replacement of four CH group ...

, which can be further used to synthesize organic conductors and

organic superconductor An organic superconductor is a synthetic organic compound that exhibits superconductivity at low temperatures. As of 2007 the highest achieved critical temperature for an organic superconductor at standard pressure is , observed in the alkali-dop ...

s. Carbon diselenide reacts with secondary amines to give dialkydiselenocarbamates: :2 Et₂NH + CSe₂ → (Et₂NH₂⁺)(Et₂NCSe₂⁻)

Safety

Carbon diselenide has high vapor pressure. It has a moderate

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

and presents an inhalation hazard. It may be dangerous due to its easy

membrane transport In cellular biology, membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes, which are lipid bilayers that contain proteins embedded in them. The ...

. It decomposes slowly in storage (about 1% per month at –30 °C). When obtained commercially, its cost is high. 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). Its smell forced an evacuation of a nearby village when it was first synthesized in 1936. Because of the odor, synthetic pathways have been developed to avoid its use..

References

{{Selenides Selenides Inorganic carbon compounds Foul-smelling chemicals Dichalcogenides IV-VI semiconductors