Swiss chemist

L. Holmia, for Stockholm). The special absorption bands of holmium were noticed in 1878 by the Swiss chemists Delafontaine and Soret, who announced the existence of an "Element X." Cleve, of Sweden, later independently discovered the element while working on erbia earth. The element is named after cleve s native city. Holmia, the yellow oxide, was prepared by Homberg in 1911. Holmium occurs in gadolinite, monazite, and in other rare-earth minerals. It is commercially obtained from monazite, occurring in that mineral to the extent of about 0.05%. It has been isolated by the reduction of its anhydrous chloride or fluoride with calcium metal. 

Ai -A-homo-4-ketones by reaction with lithium and biphenyl at The resulting dienone is transformed into the corresponding tropone by treatment with bromine. The Swiss chemists also found that base treatment of 19-mesyloxy-A " -3-oximes gives directly 4-oximino-A-homo-estra-l(10),2,4a-trienes in moderate yield. ... 

During the 1890s, these cobalt complexes attracted the attention of a Swiss chemist, Allred Werner (1866-1919). Only in his early twenties, Werner had just earned his Ph.D. in organic chemistry. He studied the cobalt complexes in detail and developed the basis for our understanding of coordination chemistry. 

Holmium (Ho, [Xe]4/n6s2), name and symbol after the Latin word for the city of Stockolm, Holmia. Discovered (1879) by P.T. Cleve even though the holmium absorption spectrum was observed the year before by the Swiss chemists J.L. Soret and M. Delafontaine. 

Awaiting the smile on a Swiss chemist s face And the tonch of a Swiss chemist s hand. 

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. 

Gadolinium - the atomic number is 64 and the chemical symbol is Gd. The name derives from the mineral gadolinite, in which it was found, and which had been named for the Finnish rare earth chemist Johan Gadolin . It was discovered by the Swiss chemist Jean-Charles Galissard de Marignac in 1886, who produced a white oxide he called Y in a samarskite mineral. In 1886, the French chemist Paul-Emile Lecoq de Boisbaudran gave the name gadolinium to Y . 

Holmium - the atomic number is 67 and the chemical symbol is Ho. The name derives from the Latin holmia for Stockholm . It was discovered in erbia earth by the Swiss chemist J. L. Soret in 1878, who referred to it as element X. It was later independently discovered by the Swedish chemist Per Theodor Cleve in 1879. It was first isolated in 1911 by Holmberg, who proposed the name holmium either to recognize the discoverer Per Cleve, who was from Stockholm or perhaps to establish his own name in history. 

Terbium - the atomic number is 65 and the chemical symbol is Tb. The name derives from the village of Ytterby in Sweden, where the mineral ytterbite (the source of terbium) was first found. It was discovered by the Swedish surgeon and chemist Carl-Gustav Mosander in 1843 in an yttrium salt, which he resolved into three elements. He called one yttrium, a rose colored salt he called terbium and a deep yellow peroxide he called erbium. The chemist Berlin detected only two earths in yttrium, i.e., yttrium and the rose colored oxide he called erbium. In 1862, the Swiss chemist Marc Delafontaine reexamined yttrium and found the yellow peroxide. Since the name erbium had now been assigned to the rose colored oxide, he initially called the element mosandrum (after Mosander) but he later reintroduced the name terbium for the yellow peroxide. Thus the original names given to erbium and terbium samples are now switched. Since Bunsen spectroscopically examined Mosander s erbium (now terbium) sample and declared that it was a mixture, the question of who actually discovered terbium, Mosander or Delafontaine remains unresolved to this day. 

Gadolinum is found in minerals bastnasite and monazite, always associated with other rare earth metals. It was isolated from yttria in 1880 by the Swiss chemist Marignac, and discovered independently in 1885 by Boisbaudran. It was named in honor of the Swedish chemist Gadolin. Its abundance in the earth s crust is 6.2 mg/kg and concentration in sea water is 0.7 ng/L. 

Oxidation of 5-substituted barbimric acids 258 with concomitant ring contraction has been shown to afford 2,4-oxazolidinediones 260 (Scheme 6.58). Similarly, examples of 5-aryl- and 5-heteroaryl-2,4-oxazolidinediones, for example, 231 and 233-240 (Table 6.8 and Fig. 6.19) have been prepared from alloxan hydrate 261. Thus, conversion of 261 to the dilauric acid intermediates 262 and reaction with sodium hydroxide gave the target compounds.Swiss chemists isolated 265 as a side product (12% yield) from the oxidation of the thymidine base in 263 during their preparation of 264 (Scheme 6.58). 

A case in point includes gadolinium, first isolated from yttria by the Swiss chemist, DeMarignac, in 1880 and later in 1885, was also obtained from ceria by the French investigator, DeBolsbaudran and lutetlum, announced in 1905 by the Frenchman, Urbain, but obtained nearly simultaneously by both the Austrian, Von Walsbach, and the American, James. 

Swiss chemist Christian Schonbein (1799-1868) publishes the first description of a fuel cell. 

Jean-Charles Galissard de Marignac, 1817-1894. Swiss chemist who discovered ytterbia and gadolima and made many important contributions to the chemistry of the rare earths. Professor of chemistry at the University of Geneva. He made precise determinations of the atomic weights of many elements, and by separating tantahc and columbic (mobic) acids, proved that tantalum and columbium (niobium) are not identical. 

Cleve s fame rests chiefly, however, on his discoveries among the rare earths. After obtaining some erbia from which all the ytterbia and scandia had been removed, and after noticing that the atomic weight of the erbium was not constant, he succeeded in resolving the earth into three constituents erbia, holmia, and thulia (21). The absorption bands of holmium had already been noticed by the Swiss chemists M. Delafontaine... 

It was the selective toxicity of the insecticide DDT that was destined to have a most profound effect on attitudes to chemical safety. DDT was a chemical that had first been synthesised decades before the Swiss chemist Muller discovered its potent insecticidal action in the late r930s. What was so remarkable about DDT was its selectivity. Even in extremely small doses, it was lethal to many species of insect yet it was remarkably non-toxic to humans even at quite high doses (Figure 6.3). The manufacture of DDT is... 

DDT was first synthesized in the 1870s, but its insecticidal properties were discovered only in 1940 by the Swiss chemist Paul Muller, who won a Nobel Prize in 1948 for his work. The U.S. military had introduced DDT for control of malaria, typhus, and other insect-carried disease by 1944, and after the end of World War II, DDT was used widely around the world for vector (mosquito) control and in agriculture. 

As is now well known, the potent psychogenic properties of LSD were discovered by the Swiss chemist Albert Hofmann, who was synthesizing molecules for Sandoz Laboratories. In 1938, Hofmann was making drugs... 

Metal complexes have characteristic shapes, depending on the metal ion s coordination number. Two-coordinate complexes, such as [Ag(NH3)2]+, are linear. Four-coordinate complexes are either tetrahedral or square planar for example, [Zn(NH3)4]2+ is tetrahedral, and [Ni(CN)4]2 is square planar. Nearly all six-coordinate complexes are octahedral. The more common coordination geometries are illustrated in Figure 20.12. Coordination geometries were first deduced by the Swiss chemist Alfred Werner, who was awarded the 1913 Nobel Prize in chemistry for his pioneering studies. 

Metal-ammonia reduction of ketones. Swiss chemists have reported a detailed study of the mechanism of this reaction, using for the most part (-l-)- 3,3-D2] camphor as substrate. The conclusions drawn have some useful practical applications. The choice of metal (Li, Na, or K) has little effect on the course of reduction to the thermodynamically more stable diastereoisomeric alcohol. The most important conclusion is that pinacol reduction can be suppressed completely in Na-NH3 reductions by use of ammonium chloride as the proton source, a finding first reported by Murphy and Sullivan.2 This salt also partially suppresses pinacol formation in Li-NHj reductions. It also suppresses reduction of enolates, and thus should decrease racemization in reduction of chiral ketones. 

Swiss chemist Albert Hofmann at Sandoz Laboratories synthesizes LSD. After initial testing on animals, Hoffman s subsequent accidental ingestion of the drug in 1943 reveals LSD s hallucinogenic properties. 

John Warcup Cornforth (1917-), Australian-English chemist, receives the Nobel Prize for his work on the stereochemistry of enzyme-catalyzed reaction. Vladimir Prelog (1906- ), Croatian-Swiss chemist, also receives the Nobel Prize in chemistry for his research into the stereochemistry of organic molecules and reactions. 

That year, R. Gordon Wasson, an enthnomycologist, published an article about Psilocybe mushrooms in Life magazine. This article brought the mushrooms to the attention of the general public for the first time. As a result of the article, thousands of people flocked to Mexico in search of the mind-altering mushroom. About that same time, the psychoactive chemical psilocybin was isolated and synthesized by Swiss chemist Albert Hofmann, who also discovered LSD (lysergic acid diethylamide). 

DDT (1,1,1 -trichloro-2,2-bis(/i-chlorophenyl)ethane) was first synthesized by Othmar Zeidle in Germany in 1874. Its insecticidal properties were not discovered until 1939 by the Swiss chemist Paul Muller. It was widely used in the Second World War to protect the troops against malaria, typhus and other vector borne diseases (Smith, 1991). After the war, DDT was widely used on agricultural crops and in disease vector control (Van Metre et al., 1997). 

Metal complexes (complex compounds or coordination compounds) are one of the most important groups of chemical compounds and form the basis of coordination chemistry. Although complex compounds date back to the 18th century, coordination chemistry was considered a science only after the formulation of the coordination theory by the Swiss chemist A. Werner at the end of the 19th century [1], During the 20th century, thousands of metal complexes were obtained, characterized, and widely applied. Much has been written on heir synthesis, structure, and properties [2-13],... 

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