Henri Moissan

In 1882, Moissan married Marie Léonie Lugan. She was the daughter of the pharmacist under whom Moissan took up his first job. The union was lucky for him because it solved much of his financial problems and he could concentrate more on his work. The couple had a son born in 1885.

Moissan died on 20 February 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.

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, USA in 1893.

Ferdinand Frederick Henri Moissan was born in Paris on 28 September 1852, in a family of Sephardic Jews, originally from South West of France. His father, Francis Ferdinand Moissan, was a junior officer in the Eastern Railway Company and his mother, Joséphine Améraldine (née Mitel), was a seamstress.

In 1864, when Henri was twelve years old, the family moved to Meaux. Here at Collège de Meaux, he came under the influence of a brilliant chemistry teacher. The teacher initiated young Henri into the magical world of chemistry. Henri became so engrossed in the subject that he studied little else.

Consequently, in 1870, he had to leave the school without acquiring the qualification necessary for getting admission to the university. He therefore, began working as an apprentice for a pharmacist in Paris. Sometime now, he saved a man, suffering from arsenic poisoning. Wiser now, he decided to pursue chemistry.

However, without the necessary qualification, he could not get admission into any recognized university. Therefore, he joined Edmond Frémy’s laboratory at Musée d'Histoire Naturelle. Here he attended lectures by E.H. Sainte-Claire Deville and Jules Henri Debray.

The following year, Moissan shifted to the laboratory of Pierre Paul Dehérain at the École Pratique des Haute Études. Incidentally, Dehérain was one of Frémy’s students and so Moissan might have joined Dehérain on Frémy’s advice. All along, he supported himself by giving tuition.

Moissan now joined School of Pharmacy once more; but this time as an assistant lecturer and a senior demonstrator. Initially he worked mainly on chromous salts, but by 1884, his attention was turned to the chemistry of fluorine. In the same year, he developed a few organic and phosphorus derivatives of the element.

In 1885, Moissan discovered that if potassium difluoride is dissolved into liquid hydrogen fluoride at certain strength the mixture remains a liquid. He also found that at sub zero temperature the solution could by electrolyzed.

He had earlier tried to electrolyze the solution at a higher temperature. It ruined the platinum equipment he was using. So he tried to carry out the same experiment at –50°C. Finally on 26 June 1886, he successfully electrolyzed the solution and isolated fluorine.

Also in 1886, he was promoted to the post of Professor of Toxicology. He continued his research on fluorine and together with his students discovered many new compounds such as bromine trifluoride, oxygen difluoride, selenium tetrafluoride. As late as in 1901, he discovered Sulfur hexafluoride, along with his doctoral student Paul Marie Alfred Lebeau.

Meanwhile, in 1889, he was elected to the Chair of Inorganic Chemistry. From 1892, Moissan’s interest shifted to a new subject. He now theorized that synthetic diamonds could be made by crystallizing cheaper form of carbon such as charcoal under the pressure of molten iron.

Isolation of fluorine by electrolyzing the solution of potassium hydrogen difluoride and liquid hydrogen fluoride is one of Moissan’s most important works. Hydrogen produced by the process accumulated at the negative electrode while the fluorine was isolated at the positive electrode. This process of isolating fluorine is followed even today.

Moissan was also a prolific writer and had more than one hundred publications to his credit. ‘Le Four Électrique’ (The Electric-Arc Furnace) published in 1897, ‘Le Fluor et ses Composé’ (Fluorine and Its Compounds) published in 1900 and ‘Traité de Chimie Minerale’ (Treatise on Inorganic Chemistry) published in five volumes from 1904 to 1906 are some of his more significant works.