(Research Department Explosive, formal name cyclotrimethylenetrinitramine, also called cyclonite, hexogen, or T₄), powerful explosive, discovered by Hans Henning of Germany in 1899 but not used until World War II; relatively safe and inexpensive to manufacture, was produced on a large scale in the U.S.; a hard, white crystalline solid, insoluble in water and only slightly soluble in some other solvents; sensitive to percussion, its principal nonmilitary use is in blasting caps; often mixed with other substances to decrease its sensitivity.