Phosgene (COCl2) is a highly toxic gas or liquid that is classified as a pulmonary irritant. Synonyms for phosgene include carbonic dichloride, carbon oxychloride, carbonyl dichloride, chloroformyl chloride, d-stoff, and green cross. The military symbol for phosgene is CG, and its United Nations/Department of Transportation number is UN#1076. The American Chemical Society's Chemical Abstracts Service (CAS) registry number for phosgene is #75-44-5. Phosgene's structure is depicted in the image below.
Phosgene structure.
Sir Humphrey Davy first synthesized phosgene in 1812 by passing carbon monoxide and chloride through charcoal. During World War I, it was used in combination with chlorine gas for combat purposes by the German army. This combination allowed phosgene emission to be hastened in cold weather. The German army switched to mustard gas in 1917 because of the development of effective gas masks. More effective agents and improved personal protective equipment make phosgene an unlikely agent to be used in future battles....