What is "diphosgene"

n. (context organic compound English) The highly chlorinated ester ''trichloromethyl chloroformate'' that is used in organic synthesis, and was once used as a military poison

Diphosgene is a chemical compound with the formula ClCOCCl. This colorless liquid is a valuable reagent in the synthesis of organic compounds. Diphosgene is related to phosgene and has comparable toxicity, but is more conveniently handled because it is a liquid, whereas phosgene is a gas.