Tabun or GA is an extremely toxic synthetic

organophosphorus compound Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective in ...

. It is a clear, colorless, and tasteless liquid with a faint fruity odor.Facts About Tabun
National Terror Alert Response System It is classified as a

nerve agent Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that ...

because it fatally interferes with normal functioning of the mammalian nervous system. Its production is strictly controlled and stockpiling outlawed by the Chemical Weapons Convention of 1993. Tabun is the first of the ''G-series'' nerve agents along with GB (

sarin Sarin (NATO designation GB G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic organophosphorus compound.soman Soman (or GD, EA 1210, Zoman, PFMP, A-255, systematic name: ''O''-pinacolyl methylphosphonofluoridate) is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiti ...

) and GF (

cyclosarin Cyclosarin or GF (cyclohexyl methylphosphonofluoridate) is an extremely toxic substance used as a chemical weapon. It is a member of the '' G-series'' family of nerve agents, a group of chemical weapons discovered and synthesized by a German te ...

). Although pure tabun is clear, less-pure tabun may be brown. It is a volatile chemical, although less so than either sarin or soman. Tabun can be destroyed with bleaching powder (calcium hypochlorite), though the reaction will produce the

poisonous Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

gas

cyanogen chloride Cyanogen chloride is a highly toxic chemical compound with the formula CNCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-te ...

. EA-4352 is an isopropyl analog to tabun.

Synthesis

Tabun was made on an industrial scale by Germany during World War II, based on a process developed by

Gerhard Schrader Gerhard Schrader (25 February 1903 – 10 April 1990) was a German chemist specializing in the discovery of new insecticides, hoping to make progress in the fight against hunger in the world. Schrader is best known for his accidental discovery of ...

. In the chemical agent factory in Dyhernfurth an der Oder, codenamed "Hochwerk", at least 12,000 metric tons of this agent were manufactured between 1942 and 1945. The manufacturing process consisted of two steps, the first being reaction of gaseous

dimethylamine Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to aroun ...

(1) with an excess of

phosphoryl chloride Phosphoryl chloride (commonly called phosphorus oxychloride) is a colourless liquid with the formula . It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from phosp ...

(2), yielding dimethylamidophosphoric dichloride (3, codenamed "Produkt 39" or "D 4") and dimethylammonium chloride (4). The

dimethylamidophosphoric dichloride Dimethylamidophosphoric dichloride is an important chemical for few industrial purposes. It is an important chemical for synthesizing phosphoramidates as well as Tabun (nerve agent), Nerve agent GA which is used as a chemical weapon. Safety T ...

thus obtained was purified by vacuum distillation and thereafter transferred to the main tabun production line. Here it was reacted with an excess of

sodium cyanide Sodium cyanide is a poisonous compound with the formula Na C N. It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its hi ...

(5), dispersed in dry

chlorobenzene Chlorobenzene is an aromatic organic compound with the chemical formula C6H5Cl. This colorless, flammable liquid is a common solvent and a widely used intermediate in the manufacture of other chemicals. Uses Historical The major use of chlorob ...

, yielding the intermediate

dimethylamidophosphoric dicyanide Dimethylamidophosphoric dicyanide is an important chemical for the final process of synthesizing Tabun (nerve agent), Tabun, a nerve agent used as a chemical weapon. Preparation Dimethylamidophosphoric dicyanide could be prepared by reacting Dime ...

(not depicted in the scheme) and

sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

(8); then, absolute

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

(6) was added, reacting with the dimethylamidophosphoric dicyanide to yield tabun (7) and

hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an ...

(9). After the reaction, the mixture (consisting of about 75% chlorobenzene and 25% tabun, along with insoluble salts and the rest of the hydrogen cyanide) was filtered to remove the insoluble salts and vacuum-distilled to remove hydrogen cyanide and excess chlorobenzene, so yielding the technical product, consisting either of 95% tabun with 5% chlorobenzene (Tabun A) or (later in the war) of 80% tabun with 20% chlorobenzene (Tabun B).

Effects of exposure

The symptoms of exposure include:

nervousness Nervous may refer to: * nervousness * Nervous system, a network of cells in an animal's body that coordinates movement and the senses ** Nervous tissue, the cells of the nervous system that work in aggregate to transmit signals Music * "Nervous" ...

/ restlessness,

miosis Miosis, or myosis (), is excessive constriction of the pupil.Farlex medical dictionary
citing: ...

(contraction of the pupil),

rhinorrhea Rhinorrhea, rhinorrhoea, or informally runny nose is the free discharge of a thin mucus fluid from the nose; it is a common condition. It is a common symptom of allergies ( hay fever) or certain viral infections, such as the common cold or COVID- ...

(runny nose), excessive salivation,

dyspnea Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathing, breathe well enough. The American Thoracic Society defines it as "a subjective experience of brea ...

(difficulty in breathing due to

bronchoconstriction Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. Causes The condition has a number of causes, the most common be ...

/secretions), sweating,

bradycardia Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, a ...

(slow heartbeat),

loss of consciousness Loss may refer to: Arts, entertainment, and media Music * ''Loss'' (Bass Communion album) (2006) * ''Loss'' (Mull Historical Society album) (2001) *"Loss", a song by God Is an Astronaut from their self-titled album (2008) * Losses "(Lil Tjay son ...

, convulsions,

flaccid paralysis Flaccid paralysis is a neurological condition characterized by weakness or paralysis and reduced muscle tone without other obvious cause (e.g., trauma). This abnormal condition may be caused by disease or by trauma affecting the nerves associ ...

, loss of bladder and bowel control,

apnea Apnea, BrE: apnoea, is the temporal cessation of breathing. During apnea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged. Depending on how blocked the airways are ( patency), there ...

(breathing stopped) and lung blisters. The exact symptoms of overexposure are similar to those created by all

s. Tabun 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 of it into the body. Very small skin dosages sometimes cause local sweating and tremors accompanied with characteristically constricted pupils with few other effects. Tabun is about half as toxic as

sarin Sarin (NATO designation GB G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic organophosphorus compound.build up in the body. The effects of tabun appear slowly when tabun is absorbed through the skin rather than inhaled. A victim may absorb a lethal dose quickly, although death may be delayed for one to two hours. A person's clothing can release the toxic chemical for up to 30 minutes after exposure. Inhaled lethal dosages kill in one to ten minutes, and liquid absorbed through the eyes kills almost as quickly. However, people who experience mild to moderate exposure to tabun can recover completely, if treated almost as soon as exposure occurs. The

median lethal dose In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ...

( LD₅₀) for tabun is about 400 mg-min/m³. Treatment for suspected tabun poisoning is often three injections of a nerve agent antidote, such as

atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically given i ...

Pralidoxime chloride Pralidoxime (2-pyridine aldoxime methyl chloride) or 2-PAM, usually as the chloride or iodide salts, belongs to a family of compounds called oximes that bind to organophosphate-inactivated acetylcholinesterase. It is used to treat organophosph ...

(2-PAM Cl) also works as an antidote; however, it must be administered within minutes to a few hours following exposure to be effective.

History

Research into ethyl dialkylaminocyanophosphonate began in the late 19th century, In 1898, Adolph Schall, a graduate student at the

University of Rostock The University of Rostock (german: link=no, Universität Rostock) is a public university located in Rostock, Mecklenburg-Vorpommern, Germany. Founded in 1419, it is the third-oldest university in Germany. It is the oldest university in continen ...

under professor

August Michaelis August Michaelis (26 December 1847 – 31 January 1916) was a German people, German chemist and discovered the Michaelis–Arbuzov reaction. Michaelis studied at the University of Göttingen and University of Jena and became professor for chemist ...

, synthesised the diethylamino analog of tabun, as part of his PhD thesis ''Über die Einwirkung von Phosphoroxybromid auf secundäre aliphatische Amine''. However, Schall incorrectly identified the structure of the substance as an imidoether, and Michaelis corrected him in a 1903 article in ''

Liebigs Annalen ''Justus Liebigs Annalen der Chemie'' (often cited as just ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig ...

'', ''Ueber die organischen Verbindungen des Phosphors mit dem Stickstoff''. The high toxicity of the substance (as well as the high toxicity of its precursors, diethylamidophosphoric dichloride and

) wasn't noticed at the time, most likely due to the low yield of the synthetic reactions used. Tabun became the first nerve agent known after a property of this chemical was discovered by pure accident in late December 1936 by German researcher

. Schrader was experimenting with a class of compounds called

organophosphate In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered a ...

s, which kill insects by interrupting their nervous systems, to create a more effective

insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...

for

IG Farben Interessengemeinschaft Farbenindustrie AG (), commonly known as IG Farben (German for 'IG Dyestuffs'), was a German chemical and pharmaceutical conglomerate (company), conglomerate. Formed in 1925 from a merger of six chemical companies—BASF, ...

, a German chemical and pharmaceutical industry conglomerate, at Elberfeld. He discovered that tabun, as well as being a potent insecticide, was enormously toxic to humans. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, as part of the Grün 3 program, a plant for the manufacture of tabun was established at Dyhernfurth (now Brzeg Dolny,

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...

), in 1939. Run by Anorgana GmbH, the plant began production of the substance in 1942. The reason for the delay was the extreme precautions used by the plant. Intermediate products of tabun were corrosive, and had to be contained in quartz or silver-lined vessels. Tabun itself was also highly toxic, and final reactions were conducted behind double glass walls. Large scale manufacturing of the agent resulted in problems with tabun's degradation over time, and only around 12,500 tons of material were manufactured before the plant was seized by the

Soviet Army uk, Радянська армія , image = File:Communist star with golden border and red rims.svg , alt = , caption = Emblem of the Soviet Army , start_date ...

. The plant initially produced shells and aerial bombs using a 95:5 mix of tabun and

, designated "Variant A". In the latter half of the war, the plant switched to "Variant B", an 80:20 mix of tabun and chlorobenzene designed for easier dispersion. The Soviets dismantled the plant and shipped it to

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

. During the

Nuremberg Trials The Nuremberg trials were held by the Allies of World War II, Allies against representatives of the defeated Nazi Germany, for plotting and carrying out invasions of other countries, and other crimes, in World War II. Between 1939 and 1945 ...

Albert Speer Berthold Konrad Hermann Albert Speer (; ; 19 March 1905 – 1 September 1981) was a German architect who served as the Minister of Armaments and War Production in Nazi Germany during most of World War II. A close ally of Adolf Hitler, he ...

, Minister of Armaments and War Production for the Third Reich, testified that he had planned to kill

Adolf Hitler Adolf Hitler (; 20 April 188930 April 1945) was an Austrian-born German politician who was dictator of Nazi Germany, Germany from 1933 until Death of Adolf Hitler, his death in 1945. Adolf Hitler's rise to power, He rose to power as the le ...

in early 1945 by introducing tabun into the

Führerbunker The ''Führerbunker'' () was an air raid shelter located near the Reich Chancellery in Berlin, Germany. It was part of a subterranean bunker complex constructed in two phases in 1936 and 1944. It was the last of the Führer Headquarters ( ...

ventilation shaft. He said his efforts were frustrated by the impracticality of tabun and his lack of ready access to a replacement nerve agent, and also by the unexpected construction of a tall chimney that put the air intake out of reach. The US once considered repurposing captured German stocks of tabun (GA) prior to production of

Sarin Sarin (NATO designation GB G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic organophosphorus compound.Allied An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...

governments, the Soviets soon abandoned tabun (GA) for

Sarin Sarin (NATO designation GB G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic organophosphorus compound.Soman Soman (or GD, EA 1210, Zoman, PFMP, A-255, systematic name: ''O''-pinacolyl methylphosphonofluoridate) is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiti ...

(GD). Large quantities of the German-manufactured agent were dumped into the sea to neutralize the substance. Since GA is much easier to produce than the other G-series weapons and the process is comparatively widely understood, countries that develop a nerve agent capability but lack advanced industrial facilities often start by producing GA. During the

Iran–Iraq War The Iran–Iraq War was an armed conflict between Iran and Iraq that lasted from September 1980 to August 1988. It began with the Iraqi invasion of Iran and lasted for almost eight years, until the acceptance of United Nations Security Council ...

of 1980 to 1988, Iraq employed quantities of chemical weapons against Iranian ground forces. Although the most commonly used agents were mustard gas and

sarin Sarin (NATO designation GB G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic organophosphorus compound.cyclosarin Cyclosarin or GF (cyclohexyl methylphosphonofluoridate) is an extremely toxic substance used as a chemical weapon. It is a member of the '' G-series'' family of nerve agents, a group of chemical weapons discovered and synthesized by a German te ...

were also used. Tabun was also used in the 1988

Halabja chemical attack The Halabja massacre ( ku, Kêmyabarana Helebce کیمیابارانی ھەڵەبجە), also known as the Halabja chemical attack, was a massacre of Kurdish people that took place on 16 March 1988, during the closing days of the Iran–Iraq War ...

. Producing or stockpiling tabun was banned by the 1993 Chemical Weapons Convention. The worldwide stockpiles declared under the convention were 2 tonnes, and as of December 2015 these stockpiles had been destroyed.

References

Bibliography

* . Republished in paperback in 1997 by Simon & Schuster, *: (Original German edition: )

Synthesis

Effects of exposure

History

See also

References

Bibliography

Further reading