Organometallic compounds of magnesium with the formula RMgX, where R is an alkyl or aryl group and X is a halogen, are universally called Grignard reagents, after Victor Grignard (1871???1935), the French chemist who discovered them. (For more information on the Grignard reagents, see Chapter 24 Organic Compounds", Section 24.5 Common Classes of Organic Compounds".) Grignard reagents can be used