(b. Paris, France. 28 September 1852; d. Paris, 20 February 1907)
Born into a family of modest means, Moissan lived in Paris until 1864, when his parents moved to Meaux. He attended the municipal college there but did not complete his studies; instead he returned to Paris to work for two years as a pharmacy apprentice. In 1872 he went to work in the laboratory of Edmond Frémy at the Muséum d’Histoire Naturelle but shortly after transferred to Pierre-Paul Dehérain’s laboratory, also at the Muséum, where he began research in plant physiology under Dehérain’s direction. Conscious of his need for more formal academic training, Moissan studied in Paris, earned the baccalauréat (1874) and the licence (1877), qualified as first-class pharmacist at the École Supérieure de Pharmacie (1879), and received the docteur ès sciences physiques from the Faculté des Sciences (1880).
Impressed with Moissan’s ability, Dehérain collaborated with his young protégé in a study of plant respiration which was published in 1874. By this time Moissan had definitely decided on inorganic chemistry as his main interest. His early investigation of the oxides of iron and related metals, and particularly the compounds of chromium, attracted the attention of Henri Sainte-Claire Deville and H. J. Debray, who encouraged him. This work formed the basis of Moissan’s doctoral thesis of 1880 and preoccupied him to a large extent during the next three years. For some time he directed a private analytical laboratory and also served as mâitre de conférences and chef des travaux pratiques at the École Supérieure de Pharmacie (1879–1883). A happy marriage with Ĺonie Lugan of Meaux in 1882 and the financial and moral support of his father-in-law enabled Moissan to pursue his scientific objectives with a minimum of distraction. That same year he also competed successfully for an agrégation at the École Supérieure de Pharmacie.
In 1884 Moissan began his remarkable research on the compounds of fluorine, which was to lead him to the isolation of this element. Previous attempts by others to obtain fluorine had not been successful because of the toxicity of fluorine compounds and the difficulty in designing suitable apparatus. Efforts by Davy, Gay-Lussac, and Thenard had not only been fruitless but injurious to their health. George J. and Thomas Knox of Ireland were seriously affected; and for the Belgian chemist Paulin Louyet and the French chemist Jérôme Nicklés these investigations proved fatal. Fŕ00E8;my was equally unsuccessful in preparing fluorine, as was George Gore of England. Although Moissan’s initial experiments to isolate fluorine, including the electrolytic decomposition of phosphorus trifluoride and arsenic trifluoride, had also failed and proved injurious to his health, he persisted and on 26 June 1886 finally succeeded. This difficult feat was accomplished by using an electrolyte of dry potassium acid fluoride dissolved in anhydrous hydrofluoric acid. For the reaction Moissan employed a platinum U-tube containing two platinum-iridium electrodes, closed by fluorite caps and cooled by methyl chloride. At the anode an electric current yielded a gas which by its strong reaction with silicon was shown to be fluorine. Moissan’s continuing investigation of the chemistry of fluorine subsequently resulted in the discovery of a number of fluorides such as carbon tetrafluoride, ethyl fluoride, methyl and isobutyl fluorides (with M. Meslans), and sulfuryl fluoride (with P. Lebeau). In collaboration with James Dewar he both liquefied (1897, 1903) and solidified fluorine (1903).
Meanwhile, Moissan had turned his attention to the production of artificial diamonds and in the process constructed his famous electric furnace, which, although simple in design, proved to be a technological tool of the first order. The original model, which he subsequently improved, was demonstrated to the Academy of Sciences in December 1892. It consisted of two blocks of lime, one laid on the other, with a hollow space in the center for a crucible, and a longitudinal groove for two carbon electrodes which produced a high-temperature electric arc. In one experiment Moissan heated iron and carbonized sugar in his electric furnace, causing the carbon to dissolve in the molten iron. He then subjected the mixture to rapid cooling in cold water, causing the iron to solidify with enormous pressure, producing carbon particles of microscopic size that appeared to have the physical characteristics of diamond. Moissan and his contemporaries believed that diamonds had finally been synthesized by this method, a conclusion that has been rejected in recent years. Nevertheless, Moissan’s electric furnace provided great impetus to the development of high-temperature chemistry. With this apparatus he prepared and studied refractory oxides, silicides, borides, and carbides; he succeeded in volatilizing many metals; and, by reducing metallic oxides with carbon, he obtained such metals as manganese, chromium, uranium, tungsten, vanadium, molybdenum, titanium, and zirconium. The electrochemical and metallurgical applications to industry of Moissan’s work became immediately apparent, for example in the large-scale production of acetylene from calcium carbide.
Academic recognition came to Moissan in December 1886 with his appointment to a professorship in toxicology at the École Supérieure de Pharmacie. In 1899 he became professor of inorganic chemistry at this same institution and in 1900 he succeeded Troost in the chair of inorganic chemistry at the Faculty of Sciences. Moissan received the Nobel Prize for chemistry in 1906 and was elected to membership in numerous learned societies both in France and abroad. Through the originality of his research and the effectiveness of his teaching, Moissan attracted an increasing number of students and exerted a remarkable influence on the progress of inorganic chemistry.
I. Original Works. Moissan was a prolific writer and his papers and monographs (written either by himself or in collaboration with others) number more than three—hundred including such major works as Le four électrique (Paris, 1897), Le fluor et ses composés (Paris, 1900), and the five-volume collaborative work which he edited, Traité de chimie minérale (Paris, 1904–1906).
Comprehensive listings of Moissan’s publications were compiled by Alexander Gutbier, Zur Erinnerung an Moissan (Erlangen, 1908), 268–285; and Paul Lebeau, “Notice sur la vie et les travaux de Henri Moissan,” in Bulletin. Socít́ chimique de France, 4th ser., 3 (1908), xxv-xxxviii.
II. Secondary Literature. For accounts of Moissan’s life and work, see Centenaire de l’ école supérieure de pharmaciede l’Université de Paris, 1803–1903 (Paris, 1904), 249–257; Alexander Gutbier, Zur Erinnerung an Moissan (Erkingen, 1908); Benjamin Harrow, Eminent Chemists of Our Time, 2nd ed. (New York, 1927), 135–154, 374–388; A. J. Ihde, The Development of Modern Chemistry (New York, 1964), 367–369; Paul Lebeau, “Notice sur la vie et les travaux de Henri Moissan,” in Bulletin. Sociáeié chimique de France, 4th ser., 3 (1908), i-xxxviii; J. R. Partington, A History of Chemistry, IV (London-New York, 1964), 911–914; Sir William Ramsay, “Moissan Memorial Lecture,” in Journal of the Chemical Society, 101 (1912), 477–488; and Alfred Stock, “Henri Moissan,” in Berichte der Deutschen chemischen Gesellschaft, 40 (1907), 5099–5130.
Evidence disputing Moissan’s claim to the production of diamonds has been presented by F. P. Bundy, et al., “Man-Made Diamonds,” in Nature, 176 (9 July 1955), 51–55.
For a discussion of the background and discovery of fluorine, see Louis Domange, “Les débuts de la chimie du fluor,” in Proceedings of the Chemical Society (June/July 1959), 172–176; and M. E. Weeks, Discovery of the Elements, 6th ed. (Easton, Pa., 1956), 755–770.