Science Fair Project Encyclopedia
|Discovered by||Gerhard Schrader|
|Chemical name||Ethyl N,N-dimethylphosphoramidocyanidate|
|Chemical family||Organophosphorous compound|
|NFPA Rating|| |
|Boiling point||247.5 °C (477.5 °F)|
|Freezing/melting point||-50 °C (-122 °F)|
|Vapor pressure||0.07 mmHg (9 Pa) at 25 °C|
|Vapor density (Air=1)||5.6|
|Liquid density||1.0887 at 25 °C/1.102 at 20 °C|
|Solubility in water||9.8 g/100 g at 25 °C / 7.2 g/100 g at 20 °C|
|Specific gravity||Not available|
|Appearance and color|| Colorless to brown liquid.|
Faintly fruity odor (none when pure)
|Fire and Explosion Data|
|Flashpoint||78 °C (172.4 °F)|
|Unusual hazards||Fires involving this chemical may resultin the formation of hydrogen cyanide|
Tabun or GA (Ethyl N,N-dimethylphosphoramidocyanidate) is an extremely toxic substance that is one of the world's most dangerous weapons of war. Because it fatally interferes with normal functioning of the mammalian nervous system, it is classified as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687, and its production and stockpiling was outlawed by the Chemical Weapons Convention of 1993. Tabun is the first of the so-called G-series nerve agents (along with GB (sarin), GD (soman) and GF (cyclosarin)).
Tabun is a colourless to brown liquid (depending on purity) It is volatile (evaporating readily at normal temperatures), although less volatile than either sarin or soman. Although odorless when pure, tabun is commonly described as having a faint fruity odor due to common manufacturing impurities.
Effects of overexposure
The exact symptoms of overexposure are similar to those created by all nerve agents, and are described in more detail in that article. Tabun, like all nerve agents, is toxic even in minute doses. The number and severity of symptoms which appear vary according to the amount of the agent absorbed and rate of entry into the body. Very small skin dosages sometimes cause local sweating and tremors with few other effects. Tabun is about half as toxic as sarin by inhalation, but tabun in very low concentrations is more irritating to the eyes than sarin.
The effects of exposure appear much more slowly when tabun is absorbed through the skin rather than inhaled: although a victim may absorb a lethal dose in 1 to 2 minutes, death may be delayed for 1 to 2 hours. Inhaled lethal dosages kill in 1 to 10 minutes, and liquid in the eye kills almost as rapidly. Most of what is known about lethal dosages are known from animal studies on monkeys.
Tabun is occasionally referred to names other than tabun or GA:
- Ethyl dimethylplosphoramidocyanidate
- Dimethylaminoethoxy-cyanophosphine oxide
- Dimethylamidoethoxyphosphoryl cyanide
- Ethyl ester of dimethylphosphoroamidocyanidic acid
- Ethyl phosphorodimethylamidocyanidate
- For an in-depth discussion, see main article on nerve agent history
Tabun, the first known nerve agent, was discovered accidentally in 1936 by the German researcher Dr. Gerhard Schrader. Dr. Schrader was experimenting with a class of compounds called organophosphates, which kills insects by interrupting their nervous systems, in order to create a more effective insecticide for the IG Farben pharmaceutical conglomerate at Elberfield . Instead of a new insecticide, however, he accidentally discovered tabun, an enormously toxic organophosphate compound still sometimes stockpiled today as a nerve agent.
During World War II as part of the Grün 3 program, a plant for the manufacture of tabun was established in Dyhernfurth (now Brzeg Dolny , Poland), producing the nerve agent under the codename Trilon-83. Run by Anorgana GmbH , the plant began production in 1942. With early manufacturing problems, only around 12,500 tons of material were manufactured before the plant was over-run by the advancing Soviet forces. The plant produced shells using a 95:5 or 80:20 mix of tabun and chlorobenzene . The Soviet government had the plant dismantled and taken back to Russia.
Like the other Allied governments, the Soviets soon abandoned GA for GB and GD. Large quantities of the German-manufactured agent were dumped into the sea. However, GA is much easier to create than the other G-series chemicals and the process is comparatively well known, as such states with less advanced industrial capabilities often start a nerve agent program with GA.
- United States Senate, 103d Congress, 2d Session. (May 25, 1994). Material Safety Data Sheet—Lethal Nerve Agent Tabun (GA). Retrieved Nov. 6, 2004.
- United States Central Intelligence Agency (Jul. 15, 1996) Stability of Iraq's Chemical Weapon Stockpile
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details