Louis Claude Cadet was a French chemist. He synthesised the first organometalic compound.
Background
Cadet was born on July 24, 1731, in Paris, the son of Claude Cadet. His father was a surgeon at the Hôtel-Dieu in Paris who died in 1745, leaving an impoverished widow and thirteen children who were adopted by friends in various localities. Later in life members of the Cadet family appropriated the names of communities in which they had been raised. Such was the case with Louis-Claude, who had been sent to the village of Gassicourt, near Mantes-la-Jolie.
Education
Upon completion of his studies at the Collège des Quatre-Nations, Cadet served an apprenticeship in pharmacy and chemistry at the establishment of Claude Humbert Piarron de Chamousset.
Career
Cadet found employment in the prestigious apothecary shop owned by Claude-Joseph Geoffroy and his son, Claude-François, both members of the Academy of Sciences. In 1753 Cadet received a six-year appointment as apothicaire-major at the Hôtel Royal des Invalides. At the conclusion of his term at the Invalides he purchased an apothecary shop on the rue St. Honoré that achieved an excellent reputation and provided him with a good income.
Cadet also served with the military outside of France, in 1761 reorganizing the pharmaceutical services of the French armies stationed in Germany. He collaborated with Berthollet and Lavoisier at the Paris mint and served as royal commissioner at the Sèvres porcelain works. Cadet was regarded by his contemporaries as a chemist of repute, as evidenced by his election to the Royal Academy of Sciences in 1766 as adjoint chimiste, with promotions to associé chimiste in 1770 and pensionnaire chimiste in 1777.
His earliest research, dating from 1755 to 1757, concerned the analysis of mineral water and was carried on initially with his teacher, Guillaume-François Rouelle. In 1757 he discovered a “fuming liquor” resulting from the distillation of arsenous oxide with potassium acetate. His discovery of this impure cacodyl substance was presented to the Academy of Sciences that same year, reported on favorably by L. C. Bourdelin and Lassone in January 1758, and published in the Academy’s Mémoires de mathématique et de physique in 1760. Using “Cadet’s fuming liquor,” Bunsen in 1837 began his important investigation of cacodyl compounds, which led to his isolation and elucidation of the cacodyl radical. Cadet’s attempt in 1759 to show the chemical nature of borax was unsuccessful. He did succeed, however, in developing more efficient methods for producing potassium acetate and ether. In 1774 his claim that mercuric oxide was reduced by heat to mercury was challenged by Baumé but supported by Sage Mathurin Brisson, and Lavoisier in a report to the Academy. Particularly noteworthy among Cadet’s many investigations made jointly with his fellow- academicians were those performed in 1772 to test the effect of heat on diamonds, in which he collaborated with Macquer and Lavoisier. Influenced by the teachings of the Geoffroys and the Rouelles, Louis-Claude Cadet worked in the mainstream of pharmaceutical, mineralogical, and analytical chemistry long cultivated on the Continent. He was comfortably settled in this tradition and, unlike his colleagues Sage and Baume, did not attack the New Chemistry, preferring to remain silent.
Cadet died on October 17, 1799, in Paris.
Achievements
Connections
Cadet was married in 1771, to Marie Thérèse Françoise Boisselet. At that time her son, fathered by Louis XV, was two years old. The boy was adopted by Cadet as Charles-Louis Cadet.