with Georges Urbain at Sorbonne University, particularly the manufacture of phosgene and the detection of mustard gas. In 1918, Grignard discovered that sodium iodide could be used as a battlefield test for mustard gas. Sodium iodide converts mustard gas to diiododiethyl sulfide, which crystallizes more easily than mustard gas. This test could detect as little as 0.01 gram of mustard gas in one cubic meter of air and was successfully used on the battlefield. His counterpart on the German side was another Nobel Prize–winning chemist, Fritz Haber. Grignard died on December 13, 1935 in Lyon at the age of 64. Grignard reaction Grignard is most noted for devising a new method for generating carbon-carbon bonds using magnesium to couple ketones and alkyl halides. This reaction is valuable in organic synthesis. It occurs in two steps: Formation of the "Grignard reagent", which is an organomagnesium compound made by the reaction an organohalide, R-X (R = alkyl or aryl; and X is a halide, usually bromide or iodide) with magnesium metal. The Grignard reagent is usually described with the general chemical formula R-Mg-X, although its structure is more complex. Addition of the carbonyl, in which a ketone or an aldehyde is added to the solution containing the Grignard reagent. The carbon atom that is bonded to Mg transfers to the carbonyl carbon atom, and the oxygen of the carbonyl carbon becomes attached to the magnesium to give an alkoxide. The process is an example of a nucleophilic addition to a carbonyl. After the addition, the reaction mixture is treated with aqueous acid to give an alcohol, and the magnesium salts are subsequently discarded. Military service Grignard was drafted into the French military as part of obligatory military service in 1892. Within the two years of his first session of service he rose to the rank of corporal. He was demobilized in 1894 and returned to Lyon to pursue his education. He was awarded a medal of the Legion of Honour and made a Chevalier in 1912 after winning the Nobel Prize. When World War I broke out, Grignard was drafted back into the military, keeping his rank of corporal. He was placed on sentry duty, and served there for several months until he was brought to the attention of the General Staff. Grignard had been wearing his Medal of the Legion of Honour, despite being ordered to take it off by a