electrolysing

SUBJECT AREA: Chemical technology

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His family, of modest means, moved in 1864 to Meaux, where he attended the municipal college; he returned to Paris before completing his education and apprenticed himself to a pharmacist. In 1872 he began work as a laboratory assistant at the Musée d'Histoire Naturelle, while continuing studies in chemistry. He qualified as a pharmacist at the Ecole Supérieure de Pharmacie in 1879, and by this time he had decided that his main interest was inorganic chemistry. His early investigations concerned the oxides of iron and related metals; his work attracted the favourable attention of Sainte-Claire Deville and was the subject of his doctoral thesis. In 1882 Moissan married Leonie Lugan, whose father provided generous financial support, enabling him to pursue his researches with greater freedom and security. He became, successively, Professor of Toxicology at the Ecole in 1886 and of Inorganic Chemistry in 1899. In 1884 Moissan began both his investigation of the compounds of fluorine and his attempts to isolate the highly reactive element itself. Previous attempts by chemists had ended in failure and sometimes injury. Moissan's health, too, was affected, but in June 1886 he succeeded in isolating fluorine by electrolysing potassium fluoride in hydrogen fluoride at −50°C (−58°F) in platinum apparatus. He was then able to prepare further compounds of fluorine, some of technological importance, such as carbon tetrafluoride. At the same time, Moissan turned his attention to the making of artificial diamonds. To achieve this, he devised his celebrated electric-arc furnace; this was first demonstrated in December 1892 and consisted of two lime blocks placed one above the other, with a cavity for a crucible and two grooves for carbon electrodes, and could attain a temperature of 3,500°C (6,332°F). It seemed at first that he had succeeded in making diamonds, but this attempt is now regarded as a failure. Nevertheless, with the aid of his furnace he was able to produce and study many substances of technological importance, including refractory oxides, borides and carbides, and such metals as manganese, chromium, uranium, tungsten, vanadium, molybdenum, titanium and zirconium; many of these materials had useful applications in the chemical and metallurgical industries (e.g. calcium carbide became the main source of acetylene).

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