a brown liquefied mixture of nitrogen dioxide and dinitrogen tetroxide, used as a nitrating, bleaching, and oxidizing agent
nitrogen tetroxide in American English
noun
Chemistry
a poisonous compound, N2O4, occurring as a colorless, water-soluble solid or liquid, dissociating into NO2: used chiefly as an oxidizer, esp. in rocket fuels, as a nitrating agent, and as an intermediate in the manufacture of nitric acid