Tabun
Tabun is the name given to the first nerve agent by its inventor.
The full name of Tabun is given as ethyl dimethylamidocyanophosphate, ethyl N,N-dimethylphosphoramidocyanidate, ethyl dimethyl- phosphoramidocyanidate, dimethylaminoethoxy-cyanophosphine oxide, dimethylamidoethoxy- phosphoryl cyanide or dimethylphosphoramidocyanidic acid, dimethyl-, ethyl ester. Its empirical formula is C2H5OP(O)(CN)N(CH3)2 or C5H11N2O2P.
It is also known as GA, as the first of the G-series nerve agents along with GB, GD and GF. It shares several common chemical properties with the other G-series agents - it is a volatile colourless to brown liquid (depending on purity), although less volatile than either GB or GD. Although odourless when pure, Tabun is commonly described as having a faint 'fruity' odour due to impurities. Exposure is treated using atropine, pralidoxime chloride, or diazepam. The LCt50 for Tabun is 150 mg-min/m³ in humans.
It was discovered accidentally in 1936 by the German researcher Gebhardt Schraeder for Bayer at Elberfield, during his investigation into organophosphates for herbicides and pesticides. During WW II as part of the Grün 3 program a plant for the manufacture of Tabun was established in Dyhernfurth (now Bzerg 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 tonnes 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 manufacture 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.
It is believed that Tabun was used during the Iran-Iraq War.
