VX is an extremely toxic synthetic chemical compound in the organophosphorus class, specifically, a thiophosphonate. In the class of nerve agents, it was developed for military use in chemical warfare after translation of earlier discoveries of organophosphate toxicity in pesticide research. In its pure form, VX is an oily, relatively non-volatile liquid that is amber-like in colour. Because of its low volatility, VX persists in environments where it is dispersed.
The substance is extremely deadly: VX fatalities occur with exposure to tens of milligram quantities via inhalation or absorption through skin. It is more potent than sarin, another nerve agent with a similar mechanism of action. On such exposure, these agents severely disrupt the body's signaling between the nervous and muscular systems, leading to a prolonged neuromuscular blockade, flaccid paralysis of all the muscles in the body including the diaphragm, and death by asphyxiation.
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