Mustard gas

Mustard gas or sulfur mustard are names commonly used for the organosulfur chemical compound bis(2-chloroethyl) sulfide, which has the chemical structure S(CH₂CH₂Cl)₂, as well as other species. In the wider sense, compounds with the substituents −SCH₂CH₂X or −N(CH₂CH₂X)₂ are known as sulfur mustards or nitrogen mustards, respectively, where X = Cl or Br. Such compounds are potent alkylating agents, making mustard gas acutely and severely toxic. Mustard gas is a carcinogen. There is no preventative agent against mustard gas, with protection depending entirely on skin and airways protection, and no antidote exists for mustard poisoning.

Also known as mustard agents, this family of compounds comprises infamous cytotoxins and blister agents with a long history of use as chemical weapons. The name mustard gas is technically incorrect; the substances, when dispersed, are often not gases but a fine mist of liquid droplets that can be readily absorbed through the skin and by inhalation. The skin can be affected by contact with either the liquid or vapor. The rate of penetration into skin is proportional to dose, temperature and humidity.

Sulfur mustards are viscous liquids at room temperature and have an odor resembling mustard plants, garlic, or horseradish, hence the name. When pure, they are colorless, but when used in impure forms, such as in warfare, they are usually yellow-brown. Mustard gases form blisters on exposed skin and in the lungs, often resulting in prolonged illness ending in death.