Urbain, George

Urbain, Georges. La coordination des atomes dans la molecule la symbolique chimique. Paris Hermann, 1933. van t Hoff, Jacobus Henricus. Ansichten uber die organische Chemie. 2 vols. Braunschweig F. Vieweg, 18781881. 

Ubaldini, Giuse ( - ), 92 Urbain, Georges (1872-1938), 247 Uvarov, Sergei Semenovich (1786-1855), 283... 

Urbain, Georges (1921) Les disciplines d une science, Paris, Doin. 

Urbain, Georges (1925) Les notions fondamentales d element chitnique et d atome, Paris, Gauthier-Villars. 

Georges Urbain (1872-1938) and Carl Auer von Welsbach confirmed the existence of the element in 1907. 

The last of the lanthanides, this metal is also the hardest and the densest of them. It is a component of cerium mischmetal. Lutetium has some applications in optoelectronics. Shows great similarities to ytterbium. Its discoverer, Georges Urbain, carried out 15 000 fractional crystallizations to isolate pure lutetium (record ). The element has special catalytic properties (oil industry). 176Lu is generated artificially and is a good beta emitter (research purposes). 177Lu has a half-life of six days and is used in nuclear medicine. 

From 1924 to 1933, the editors of the Annales de Physique were Marcel Brillouin, Aime Cotton, and Jean Perrin and the editors of the Annales de Chimie were Charles Moureu, Georges Urbain, and Marcel Delepine. 

In the 1930s, the French chemist Georges Urbain argued that the carbon tetrahedron is a valuable mental construct but that it cannot be a "model," because in physical science a model must take mechanism and force into account. The representation of the double bond by one of the sides of a double tetrahedron is a pure symbol. 

Professeur Charles Moureu), le 10 mars 1923," 125164, in Job, Formes chimiques de transition, ed. Jean Perrin and Georges Urbain (Paris Societe d Editions Scientifiques, 1931) and "Les reactions intermediaries dans la catalyse," rapport presente au deuxieme Conseil Solvay de Chimie tenu a Bruxelles du 16 au 24 avril 1925," 165193, Solvay II, diagrams on 172173, 174. 

Perrin, Jean, and Georges Urbain, eds. Formes chimiques de transition. Paris Societe d Editions Scientifiques,... 

Lutetium (Lu, [Xe]4/ 145 / 6.v2), name and symbol after the Latin word Lutetia (Paris). Discovered (1907) by Georges Urbain and Carl Auer von Welsbach. Silvery white metal. 

Dysprosium - the atomic number is 66 and the chemical symbol is Dy. The name derives from the Greek dysprositos for hard to get at , due to the difficulty in separating this rare earth element from a holmium mineral in which it was found. Discovery was first claimed by the Swiss chemist Marc Delafontaine in the mineral samarskite in 1878 and he called it philippia. Philippia was subsequently found to be a mixture of terbium and erbium. Dysprosium was later discovered in a holmium sample by the French chemist Paul-Emile Lecoq de Boisbaudron in 1886, who was then credited with the discovery. It was first isolated by the French chemist George Urbain in 1906. 

Lutetium Lu 1907-08 (Paris, France) and (Vienna, Austria) Georges Urbain (French) and Carl von Welsbach (Austrian) 302... 

Mana F, Georges B, Reynaert H, Ham HR, Urbain D (2000) Acta Gastro-Enterol Belg... 

Austrian mineralogist Carl Auer von Welsbach and French scientist Georges Urbain Expensive and rare with few commercial applications name derives from the ancient Roman name for Paris. 

Indium, unlike germanium, is found in zinc blendes which are geologically old. Whereas cadmium occurs mainly in the well-formed crystals of pure zinc blende, indium is found in the fine-grained mixtures in thin ramifying cracks (84). Professor Georges Urbain found that blendes rich in germanium are usually rich also in gallium put poor in indium (84, 87). 

In 1907 Georges Urbain separated ytterbia into two constituents. By repeated fractional crystallization of ytterbium nitrate from nitric acid solution, he obtained two oxides with different properties. One of these he named neoytterbia in order, as he said, to leave to the illustrious... 

Georges Urbain, 1872-1938. French chemist, painter, sculptor, and musician. President of the Societe de Chimie and of the International Committee on Atomic Weights. His enthusiasm for research was acquired from Pierre Curie and Charles Friedel, See ref. (70)... 

Memorial Plaque Designed by Georges Urbain in Honor of the Schiitzen-berger Centennial. This is a fine example of Professor Urbain s artistic ability. 

Professor Curie continued his researches on the growth of crystals, and his young wife prepared for her examinations. Many chemists consider her dissertation (55) to be the most remarkable thesis ever presented for the doctorate. She continued the work begun by Becquerel, and tested most of the known elements, including a number of rare ones loaned by E.-A. Demarpay and Georges Urbain, with Prof. Curie s piezoelectric quartz electrometer, and found that thorium and uranium were the only ones whose compounds produced appreciable ionization (26, 54, 55). The radioactivity of thorium was discovered independently by Gerhardt Carl Schmidt, professor of physics at the University of Munster (25). 

Moseley s work not only shed much fight on the periodic system and the relationships between known elements and the radioactive isotopes, but was also a great stimulus in the search for the few elements remaining undiscovered (11). One of the first chemists to utilize the new method was Professor Georges Urbain of Paris, who took his rare earth preparations to Oxford for examination. Moseley showed him the characteristic fines of erbium, thulium, ytterbium, and lutetium, and confirmed in a few days the conclusions which Professor Urbain had made after twenty years... 

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