Selenium monochloride | |
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Selenium monochloride |
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Other names
Dichlorodiselenide, Diselenium dichloride, Selenium chloride, 1,2-dichlorodiselane |
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Identifiers | |
CAS number | 10025-68-0 |
Properties | |
Molecular formula | Se2Cl2 |
Molar mass | 228.83 g/mol |
Appearance | Reddish-brown oily liquid |
Density | 2.7741 g/cm3 |
Melting point |
-85 °C (223.15 K) |
Boiling point |
127 °C at 0.997 atm (400.15 K at 0.997 atm) |
Solubility in water | insoluble; sol in CHCl3, CS2, MeCN |
Solubility | Soluble in dry chloroform and carbon disulfide |
Hazards | |
R-phrases | 23/24/25-34 |
S-phrases | 22-26-36/37/39-45 |
(verify) (what is: / ?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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Infobox references |
Selenium monochloride is an inorganic compound with the formula Se2Cl2. Although it is called selenium monochloride, a more descriptive name might be diselenium dichloride. It is a reddish-brown, oily liquid that is hydrolyses slowly. It exists in chemical equilibrium with SeCl2, SeCl4, chlorine, and elemental selenium.[1] Selenium monochloride is mainly used as a reagent for the synthesis of Se-containing compounds.
Contents |
Selenium monochloride exhibits C2 molecular symmetry, similar to hydrogen peroxide. The bond length of the Se-Se bond is predicted to be 2.253 Å and the Se-Cl bonds are both 2.227 Å.[2]
In acetonitrile solutions, it exists in equilibrium with SeCl2 and SeCl4.[3]
Selenium monochloride was originally produced by the chlorination of selenium.[4] An improved method involves the reaction of a mixture of selenium, selenium dioxide, and hydrochloric acid:[5]
A dense layer of selenium monochloride settles from the reaction mixture, which can be purified by dissolving it in fuming sulfuric acid and reprecipitating it with hydrochloric acid. A second method for the synthesis involves the reaction of selenium with oleum and hydrochloric acid:[5]
The crude selenium monochloride product is collected via distillation.
Selenium monochloride is an electrophilic selenizing agent, and thus it reacts with simple alkenes to give bis(β-chloroalkyl)selenide and bis(chloroalkyl)selenium dichloride.[6] It converts hydrazones of hindered ketones into the corresponding selones, the structural analogs of ketones whereby the oxygen atom is replaced with a selenium atom.[6] Finally, the compound has been used to introduce bridging selenium ligands between the metal atoms of some iron and chromium carbonyl complexes.[6]
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