JEAN-CHARLES GALISSARD DE MARIGNAC Physical and organic chemistry, atomic masses, and rare earths

Jean-Charles Galissard de Marignac (1817-1894) was a Swiss chemist who investigated the derivatives of naphthalene with nitric acid and synthesized and described the properties of nitronaphthalic acid, trinitronaphthalene, nitronaphthalese, naphthalamide, and a series of naphthalates. Marignac extended the work of Schönbein about the nature and properties of ozone and proved that the gas did not contain nitrogen although he was unable to decide if ozone was composed of pure oxygen or oxygen and hydrogen. He also developed a simple procedure for producing concentrated sulfuric acid by the partial crystallization of the acid at low temperatures, determined that at high temperatures ammonium chloride decomposed into ammonia and hydrogen chloride, and studied the thermal properties of liquids (specific heat, density and
expansion) particularly of aqueous solutions of halides nitrates, sulfates, chromates, carbonates, acetates, oxalates, and phosphates. His most important contribution was the careful determination of the atomic mass of a large number of elements. He investigated the rare earths and discovered gadolinium and ytterbium (although he did not separate them from their oxides), purified terbium, etc.