Lewisite
From Freepedia
| This article forms part of the series |
| (A subset of Weapons of mass destruction) |
| Lethal agents |
|---|
| Blood agents |
| Cyanogen chloride |
| Hydrogen cyanide |
| Blister agents |
| Lewisite |
| Sulfur mustard gas (HD and THD, HT) |
| Nerve agents |
| G-Agents |
| GA (tabun), GB (sarin) GD (soman), GF (cyclosarin) |
| V-Agents |
| VE, VG, VM, VX |
| Pulmonary agents |
| Chlorine |
| Chloropicrin (PS) |
| Phosgene (DP) |
| Diphosgene (CG) |
| Non-lethal agents |
| Incapacitating agents |
| BZ / Agent 15 |
| KOLOKOL-1 |
| Riot control agents |
| Pepper spray (OC) |
| CS gas |
| CN gas |
| CR gas |
Lewisite is a chemical compound from a chemical family called arsines. While it is a colourless and odourless liquid when pure it is usually found as a oily, brown liquid with a distinct odour similar to geraniums. It is a chemical weapon, acting as a vesicant and lung irritant, and can be used in combination as mustard-lewisite.
It can easily penetrate ordinary clothing and even rubber; upon skin contact it causes immediate pain and itching with a rash and swelling. Blisters develop after 12 hours, and discomfort lasts for 2 to 3 days. Sufficient absorption can cause systemic poisoning leading to liver necrosis or death.
Inhalation causes a burning pain, sneezing, coughing, vomiting, and possibly lung oedema. Ingestion results in severe pain, nausea, vomiting, and tissue damage. Generalised symptoms also include restlessnesss, weakness, subnormal temperature and low blood pressure.
Lewisite is usually found as a mixture of isomers, 2-chlorovinylarsonous dichloride should predominate but often bis(2-chloroethenyl)arsinous dichloride and tris(2-chlorovinyl) arsine are present. Lewisite can be given any of the preceding names and is also sometimes described as 2-chlorovinyldichloroarsine, (2-chloroethenyl)arsinous dichloride or dichloro- (2-chlorovinyl) arsine. Its empirical formula is C2H2AsCl3 and can be represented as ClCHCHAsCl2. Its molecular mass is 207.32 g/mol, melting point −18 °C, boiling point 190 °C, at 20 °C its vapour pressure is 0.35 mm Hg (47 Pa) and its density is 1.89 g/cm³. Lewisite hydrolyses in water to form hydrochloric acid, and in contact with alkaline solutions can form poisonous trisodium arsenate.
It is named after the US chemist and soldier Winford Lee Lewis. He discovered it at the Catholic University of America, Washington, D.C. in 1918 by the combination of acetylene and arsenic trichloride, based on the 1904 work of Nieuwland. It was developed into a secret weapon at Nilo Park, Ohio and given the name "the new G-34" to confuse its development with mustard gas. It was not used in the First World War, but experimented with in the 1920s as the "Dew of Death."
After World War I, the US became interested in Lewisite because it was not flammable. It had the military symbol of M1 up into World War II, when it was changed to L. Field trials with Lewisite during the World War II demonstrated that casualty concentrations were not achievable under high humidity due to its rate of hydrolysis and its charactistic odor and lacrymation forced troops to don masks and avoid contaminated areas. The United States produced about 20,000 tons of Lewisite, keeping it on hand primarily as an antifreeze for mustard gas or to penetrate protective clothing in special situations. It was replaced by the Blister Agent HT (a 60:40 mixture of mustard gas and O Mustard), and determined obsolete in the 1950's. It is effectively treated with BAL, British anti-Lewisite. Stockpiles of Lewisite were neutralized with bleach and dumped into the Gulf of Mexico.
