MOISSAN, HENRI (1852-1907), French chemist, was born at Paris on Sept. 28, 1852. He was educated in Fremy's laboratory and attended lectures by Sainte-Clair, Deville and Debray. In 1879 he was appointed to a junior post in the Agronomic institute, Paris, and was subsequently (1886) pro fessor of toxicology and of inorganic chemistry (1889) at the School of Pharmacy, and of inorganic chemistry at the Sorbonne (1900). He was awarded the Lacase prize in 1887 and the Nobel prize for chemistry in 1906; he died in Paris on Feb. 20, 1907.
Moissan's first research was on a biological problem and dealt with the interchange of oxygen and carbon dioxide in leaves, but he soon went over to inorganic chemistry. His early work in this field was on the oxides of the iron group metals, and of chromium ; he also made a careful study of the chromous salts. In 1884 he turned to the study of fluorene and prepared several new compounds, including phosphorus and organic derivatives. In 1885 he found that potassium fluoride could be dissolved in certain proportions in liquid hydrofluoric acid to give a solution which conducted electrolytically and which remained liquid at low temperatures. A year later by electrolysing this solution in a platinum tube using platinum-iridium electrodes he obtained for the first time the wonderfully active fluorine gas. He made a full study of the properties of the gas and of its combinations with other elements. In 1892 Moissan developed the electric
arc furnace as a means of obtaining very high temperatures for experimental work; by its aid he prepared many new compounds, especially carbides, silicides and borides, and melted and volatilized substances which had previously been regarded as infusible. He prepared tiny artificial diamond?. (see GEMS, ARTIFICIAL) by cool ing very rapidly a solution of carbon in molten iron, and also discovered carborundum (silicon carbide). He studied the chem istry of the carbides and the action on them of water, and was led by the results to suggest that petroleum formation may be due to a similar process occurring in the earth. Moissan also prepared the hydrides of calcium, sodium and potassium, and found them to be non-conductors of electricity.
His published works include Le four electrique (1897) and Le Fluor et ses composes (190o), besides numerous papers, mainly in the Comptes rendus of the Societe Chimique. A Traite de Chimie minerale (5 vols.) was published under his direction in 1904-06.