HN3 (nitrogen mustard)

Tris(2-chloroethyl)amine is the organic compound with the formula N(CH₂CH₂Cl)₃. Often abbreviated HN3, it is a powerful blister agent and a nitrogen mustard gas (although it is not a gas) used for chemical warfare. HN3 was the last of the nitrogen mustard agents developed. It was designed as a military agent and is the only one of the nitrogen mustards that is still used for military purposes. It is the principal representative of the nitrogen mustards because its vesicant properties are almost equal to those of HD and thus the analogy between the two types of mustard is the strongest. As a vesicant the use and production is strongly restricted within the Chemical Weapons Convention where it is classified as a Schedule 1 substance.