Background

Henri Moissan was born on September 28, 1852 in Paris, Ile-de-France, France. He is the son of Francois Ferdinand Moissan and Josephine Mitel Moissan. The family lived modestly. His father was a clerk and his mother a seamstress. In 1864 they moved to Meaux, about twenty-five miles east of Paris.

Education

Henri Moissan was educated at the municipal school and was influenced by a mathematics and science teacher who gave him private lessons. His family, however, could not afford to pay for him to complete the courses in physics and classical languages that would have given him his baccalaureate, a necessity for university admission. In 1870 he was apprenticed briefly to a watchmaker before joining the army to defend Paris from the Prussians. He was finally apprenticed to a pharmacist in 1871. He planned to enroll in the three-year course at the Ecole Superieure de Pharmacie to earn the only qualification open to him, pharmacist second-class.

Instead he was attracted into the laboratories of Edmond Fremy’s School of Experimental Chemistry at the Paris Museum of Natural History. There he engaged in research, supported himself by tutoring, and finished the courses needed for his degree. He received the baccalaureate in 1874, and thereafter a series of higher degrees: license (Bachelor of Science) in 1877, pharmacist first-class in 1879, and a doctorate in 1880.

Career

Although Henri Moissan's earlier research had been in the chemistry of plant respiration, his doctoral dissertation dealt with pyrophoric iron and various oxides of that metal. He was interested only in inorganic chemistry, and this was the direction he would take for the rest of his career. In the course of this research he also concerned himself with chromium salts, and he developed a process for the preparation of pure chromium by reduction in a stream of hydrogen.

Moissan began teaching at the Ecole Superieure de Pharmacie, and in 1880 he was named associate professor. In 1884 Moissan attempted to isolate the element fluorine. This was a long-standing problem that had eluded many notable scientists of the day. It was also a dangerous problem because of the high toxicity of fluoride compounds. Moissan’s mentor Fremy had claimed production of fluorine by electrolysis (passing an electric current through it) of molten potassium fluoride, but at the temperature necessary for fusion the gas immediately attacked the platinum electrodes and thus could not be isolated. Fremy had also produced anhydrous hydrogen fluoride, but it could not be electrolyzed because it did not conduct electricity.

Moissan found that potassium acid fluoride which had been dissolved in hydrogen fluoride did conduct electricity. With an apparatus consisting of a platinum U- tube capped with plugs of fluorite (calcium fluoride) and fitted with iridium-platinum electrodes that resisted attack by fluorine, he produced the gaseous element at -50 degrees Celsius to keep its reactivity to a minimum. This was in 1886, and over the next several years he devoted his major research efforts to reactions and compounds of fluorine, producing thionyl fluoride and sulfuryl fluoride and the unreactive carbon tetrafluoride and sulfur hexafluoride, as well as a number of organic alkyl fluorides. Later, with James Dewar, he produced liquid fluorine and, in 1903, solid fluorine. The element proved reactive down to its liquefaction temperature of -188 degrees Celsius. It is in fact the most reactive of all the elements, forming compounds even with the "inert" gases krypton, xenon, and radon; water itself “burns” in a fluorine atmosphere with a visible flame.

After an excursion into the chemistry of boron, during which time he produced the pure element and studied a number of its compounds, Moissan became interested in the laboratory production of diamonds. To force carbon from its graphite form into the density of a diamond, great heat and pressure was required. Moissan reasoned that this might be accomplished by dissolving carbon into molten iron at very high temperature, then quickly cooling the solution in such a way that the mass formed a solid “skin” that would generate pressure on the still-liquid interior. However, the crystals he produced in this way were considered by later researchers not to be true diamonds because the pressure required to create diamonds is about five times greater than Moissan’s method produced. The most important result of these experiments proved to be an instrument he had developed to conduct them. Moissan devised an electric arc furnace capable of producing temperatures as great as 3500 degrees Celsius.

The design of the furnace was simple. Two blocks of lime were laid on top of one another; the lower block was grooved to admit the electrodes and their leads, and the center had room for a crucible. A smaller hollow in the upper block formed a lid for the chamber. The electric furnace opened a new world of high- temperature chemistry. Within a few years of its development, Moissan prepared pure samples of metallic vanadium, chromium, manganese, zirconium, niobium, molybdenum, tantalum, tungsten, thorium, and uranium. He also synthesized previously unknown metallic borides, carbides, and silicides, including the extremely hard and refractory silicon carbide, which was later produced by a more practical method under American patent as the abrasive Carborundum.

Moissan was professor of toxicology at the Ecole Supérieure de Pharmacie from 1886 to 1899, when he became professor of inorganic chemistry. The following year, he accepted the chair of Inorganic Chemistry in the Faculty of Sciences of the University of Paris, which he held until his death. Moissan’s health was adversely affected by his work with fluorine and its compounds. Moissan died on February 20, 1907 shortly after his return from Stockholm, where he went to receive his Nobel Prize. It was a sudden death and might have been caused by acute case of appendicitis.

Achievements

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  Henri Moissan is well noted for his isolation of fluorine gas and development of Moissan electric furnace. He devised a commercially profitable method of producing acetylene. This process of isolating fluorine is followed even today. Moissanite, naturally found silicon carbide regarded as an alternative to diamond, has been named after Henri Moissan. He discovered this rare mineral from rock samples of a meteoroid found in Arizona, United States in 1893.
  
  Moissan was also a prolific writer and had more than one hundred publications to his credit. Le Four Électrique, Le Fluor et ses Composé, Traité de Chimie Minerale are some of his more significant works.

Works

More photos

• book

  • Le Four Electrique

    (French Edition)

    1897
  • La fluor et ses composés

    (French Edition)

    1900
  • Traité de chimie minérale

    (French Edition)

    1906

Membership

Henri Moissan was elected a member of the Académie de Médecine (1888), Académie des Sciences (1891), Conseil d’Hygiène de la Seine (1895), and the Comité Consultatif des Arts et Manufactures (1898).

Connections

In 1882 Henri Moissan married Marie Leonie Lugan, the daughter of a Meaux pharmacist who took an interest in Moissan’s scientific progress and provided financial support. In 1885 they had their only child, Louis Ferdinand Henri, who was killed in 1915 in one of the early battles of World War I.

Father:

Francois Ferdinand Moissan

Mother:

Josephine Mitel Moissan

Spouse:

Marie Leonie Lugan

Son:

Louis Ferdinand Henri Moissan

teacher:

Henri Deville

teacher:

Henri Debray

References

• Great Chemists
  1961
• Contemporary Authors
  1998