Carbon diselenide

Carbon diselenide

Names
Other names Carbon selenide, diselenoxomethane, methanediselone
Identifiers
CAS Number	506-80-9 Y
ChemSpider	61481 N
Jmol 3D model	Interactive image
PubChem	68174
InChI InChI=1S/CSe2/c2-1-3 N Key: JNZSJDBNBJWXMZ-UHFFFAOYSA-N N InChI=1/CSe2/c2-1-3 Key: JNZSJDBNBJWXMZ-UHFFFAOYAM
SMILES [Se]=C=[Se]
Properties
Chemical formula	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)
Solubility in water	0.054 g/100 mL
Solubility	soluble in CS2, toluene
Dipole moment	0 D
Thermochemistry
Specific heat capacity (C)	5032 J/mol K
Std molar entropy (So298)	263.2 J/mol K
Std enthalpy of formation (ΔfHo298)	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 YN ?)
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.

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.

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]–. The polymer is a semiconductor with a room-temperature conductivity of 50 S/cm.

In addition, carbon diselenide is a precursor to tetraselenafulvalenes, 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:

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.

Mixed with air, carbon diselenide (CSe₂) releases an extremely offensive odor. 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. Because of the odor, synthetic pathways have been developed to avoid its use.