Vauquelin worked as Fourcroy’s assistant for eight years, becoming his close friend and collaborator: they published over fifty joint research papers. He also collaborated with Brongniart, and succeeded him as professor of chemistry at the Jardin des Plantes. He taught Thénard, Chevreul and Stromeyer, Thénard coming to him (impoverished, of peasant origins) just as he had gone to Fourcroy. Berthollet, Lavoisier and Gay-Lussac were all friends. Fourcroy and Haüy advised him on the naming of chromium (because of its colourful compounds). He protected his student Orfila, the founder of toxicology, during the Peninsular War.