Thionyl chloride

Thionyl chloride is an inorganic compound with the chemical formula SOCl2. It is a moderately volatile colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent.

Safety

SOCl2 is highly reactive and can violently release hydrochloric acid upon contact with water and alcohols. It is also a controlled substance under the Chemical Weapons Convention, where it is listed as a Schedule 3 substance, since it is used in the "di-di" method of producing G-series nerve agents[citation needed] and the Meyer and Meyer–Clarke methods of producing sulfur-based mustard gases.