Selenium oxydichloride
Selenium oxydichloride is the inorganic compound with the formula SeOCl2. It is a colorless liquid. With a high dielectric constant and high specific conductance, it is an attractive solvent. Structurally, it is a close chemical relative of thionyl chloride SOCl2, being a pyramidal molecule.
Preparation and reactions
Selenium oxydichloride can be prepared by several methods, and a common one involves the conversion of selenium dioxide to dichloroselenious acid followed by dehydration:The original synthesis involved the redistribution reaction of selenium dioxide and selenium tetrachloride.
Pure selenium oxydichloride autoionizes to a dimer:
The SeOCl2 is generally a labile Lewis acid and solutions of sulfur trioxide in SeOCl2 likely form +− the same way.
The compound hydrolyzes readily to form hydrogen chloride and selenium dioxide, and very few organic compounds dissolve in it without reaction. At elevated temperatures, it is a strong oxidizer, yielding a chloride, selenium dioxide, and diselenium dichloride.