Cerium discovery

After having read the two publications, N.-L. Vauquelin in Paris wrote his own paper in which, for some inscrutable reason, he asserted that the two Swedes had made the cerium discovery, informed Klaproth about it, and also sent a sample of the heavy stone from Bastnaes. Klaproth had then published the investigation in his own name. This was a terrible accusation, which naturally made Klaproth very indignant. That a young unknown Herr Berzelius, 24 years of age and without experience, should compete with... 

In 1942, the Mallinckrodt Chemical Company adapted a diethylether extraction process to purify tons of uranium for the U.S. Manhattan Project [2] later, after an explosion, the process was switched to less volatile extractants. For simultaneous large-scale recovery of the plutonium in the spent fuel elements from the production reactors at Hanford, United States, methyl isobutyl ketone (MIBK) was originally chosen as extractant/solvent in the so-called Redox solvent extraction process. In the British Windscale plant, now Sellafield, another extractant/solvent, dibutylcarbitol (DBC or Butex), was preferred for reprocessing spent nuclear reactor fuels. These early extractants have now been replaced by tributylphosphate [TBP], diluted in an aliphatic hydrocarbon or mixture of such hydrocarbons, following the discovery of Warf [9] in 1945 that TBP separates tetravalent cerium from... 

Cerium was the first rare-earth element discovered, and its discovery came in 1803 by Jons Jakob Berzelius in Vienna. Johann Gadohn (1760—1852) also studied some minerals that were different from others known at that time. Because they were different from the common earth elements but were all very similar to each other, he named them rare-earth elements. However, he was unable to separate or identify them. In the 1800s only two rare-earths were known. At that time, they were known as yttria and ceria. Carl Gustav Mosander (1797—1858) and several other scientists attempted to separate the impurities in these two elements. In 1839 Mosander treated cerium nitrate with dilute nitric acid, which yielded a new rare-earth oxide he called lanthanum. Mosander is credited with its discovery. This caused a change in the periodic table because the separation produced two new elements. Mosander s method for separating rare-earths from a common mineral or from each other led other chemists to use... 

Similar to the discovery of many other elements, cerium was detected simultaneously by several different scientists. In 1803 the Swedish chemist Jons Jakob Berzehus (1770—1848)... 

Three groups had roles in the discovery of nobelium. First, scientists at the Nobel Institute of Physics in Stockholm, Sweden, used a cyclotron to bombard Cu-244 with heavy carbon gC-13 (which is natural carbon-12 with one extra neutron). They reported that they produced an isotope of element 102 that had a half-life of 10 minutes. In 1958 the team at Lawrence Laboratory at Berkeley, which included Albert Ghiorso, Glenn Seaborg, John Walton, and Torbjorn Sikkeland, tried to duplicate this experiment and verify the results of the Nobel Institute but with no success. Instead, they used the Berkeley cyclotron to bombard cerium-... 

The discovery of samarium is credited to Boisbaudran, who in 1879 separated its oxide, samaria from Mosander s didymia, the mixture of rare earth oxides from which cerium and lanthanum were isolated earher. Demarcay in 1901 first identified samaria to be a mixture of samarium and europium oxides. The element got its name from its mineral, samarskite. The mineral, in turn, was named in honor of the Russian mine official Col. Samarki. 

Period of First Industrial Usage. By iitprovement of this first discovery there arose the first industrial consunption of rare earths and the hour of birth of the rare earth industry in the year 1891, when Auer vcn Welsbach reported his patents for the Auer incandescent mantle v ch is conposed of 99 % thorium oxide and 1 % cerium oxide. Ihis light was sip>erior for decades to electric light. It was cheaper so that until the year 1935 approximately 5 billion incandescent mantles had been produced and consumed in the world. 

The lanthanide metals should also be investigated to higher pressures than previously applied. It is not excluded that their 4 f electrons also participate in bonding as do the 5 f s of Bk and Cf, after the dhcp, ccp and, possibly, distorted fee phases have been reached. An indication of this possibility can be seen in the recent discovery of the a-uranium structure type in praseodymium (Pr IV) . This structure type was previously observed for cerium, but was thought to be restricted to that metal which has an exceptional position among the lanthanide elements. 

From the early 1960s onwards, the use of lanthanide (Ln) based catalysts for the polymerization of conjugated dienes came to be the focus of fundamental studies [31]. The first patent on the use of lanthanides for diene polymerization originates from 1964 and was submitted by Union Carbide Corporation (UCC) [32,33]. In this patent the use of binary lanthanum and cerium catalysts is claimed. Soon after this discovery by UCC, Throckmorton (Goodyear) revealed the superiority of ternary lanthanide catalyst systems over binary catalyst systems. The ternary systems introduced by Throckmorton comprise a lanthanide compound, an aluminum alkyl cocatalyst and a halide donor [34], Out of the whole series of lanthanides Throckmorton... 

Nor was Mendeleev s revolutionary Periodic Table a help. When he first published his Periodic Table in 1869, he was able to include only lanthanum, cerium, didymium (now known to have been a mixture of Pr and Nd), another mixture in the form of erbia, and yttrium unreliable information about atomic mass made correct positioning of these elements in the table difficult. Some had not yet been isolated as elements. There was no way of predicting how many of these elements there would be until Henry Moseley (1887-1915) analysed the X-ray spectra of elements and gave meaning to the concept of atomic number. He showed that there were 15 elements from lanthanum to lutetium (which had only been identified in 1907). The discovery of radioactive promethium had to wait until after World War 2. 

Credit for the discovery of cerium is sometimes given to scientists who studied the black rock of Bastnas earlier. These scientists included Swedish chemists Jons Jakob Berzelius (1779-1848) and Wilhelm... 

Cerite was thoroughly studied by Swedish chemist Carl Gustav Mosander (1797-1858). In 1839, Mosander was able to separate cerite into two parts, which he called cerium and lanthanum. Mosander believed he had found two new elements. Two years later, however, he learned that his lanthanum was not an element but a mixture of two parts. Mosander called these two new parts lanthanum and didymium. Mosander chose the name didymium because it means twin. He said that didymium was like an identical twin to lanthanum. Chemists later confirmed that two of Mosander s discoveries were really new elements cerium and lanthanum. 

Swedish chemists Jons Jakob Berzelius and Wilhelm Hisinger and German chemist Martin Klaproth discover the black rock of Bastnas, Sweden, which led to the discovery of several elements. Berzelius and Hisinger originally assume the rock is a new element, which they name cerium. 

In 1789, Klaproth isolated zirconia from zircon, and in the same year he discovered uranium in the ore pitchblende. He confirmed the existence of strontia (discovered by Thomas Charles Hope [1766-1844]) in 1795 and discovered titanium that same year. In 1797, he isolated chromium, while in 1789 he announced the discovery of tellurium. Klaproth shares a three-way discovery of cerium with Wilhelm Hisinger (1766-1852) and Jons Jakob Berzelius (1779-1848). 

Lanthanum. La at. wt 138,9055 at. no. 57 valence 3. A rare earth metal. Two naturally occurring i 0-ropes 159La <99.911 %) La (0.089%) IJ La is radioactive, 1-12 X 1011 years artificial radioactive isotopes 125-137 140-144. Estimated abundance in earth s crust 5-1 ppm. Found in association with cerium and other light Ian-thanons. Minerals of commercial interest are monazite bastnaesite and cerite. Discovery and isoln Mosander ... 

The order of the discovery of the cerium earths is summarised in the following scheme —... 

The progress of modem chemistry has added largely to the number of the elementary metals. Before the middle of last century the metals known were only such as had long been used in the arts or in medicine, and did not exceed twelve in number. From that period many new metals were gradually discovered in the mineral kingdom and, in 1807, Davy s discovery of the metals of the alkalies at once added a numerous class of metals to the list. Wollaston and Smithson Tennant had previously, in 1803, discovered the four remarkable metals associated with platinum in its ores. The whole number of ascertained metals is now forty-two and within the last year Mosand er has announced the discovery of three new metals, accompanying cerium and yttrium, which, if established, will raise the number to forty-five. 

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