Earth lanthanide

The sohds are treated with hydrochloric acid at 70°C at pH 3—4. The thorium hydroxide [13825-36-0] remains iasoluble and can be filtered off. Small amounts of trace contaminants that carry through iato solutioa, such as uranium and lead as well as some thorium, are removed by coprecipitation with barium sulfate ia a deactivatioa step. The resultiag product, after SX-removal of the heavy La fractioa, is a rare-earth/lanthanide chloride,... 

Compared to the wealth of data concerning the solid- and solution-state structures of lithium (di)organophosphides, reports of heavier alkali metal analogues are sparse. Indeed, the first crystallographic study of a homometallic heavier alkali metal (di)organophosphide complex was reported only in 1990 (67) and the majority of such complexes have been reported in the past 3 years. Interest in these complexes stems mainly from their enhanced reactivity in comparison to equivalent lithium complexes, which is particularly useful for the synthesis of alkaline earth, lanthanide, and actinide organophosphide complexes. 

Coupled reduction with platinum group metals. Very pure metals of the alkaline earth, lanthanide and actinide series can be prepared from their oxides (or fluorides) by coupled reduction by pure hydrogen in presence of platinum group metals (see 6.7.2.2). 

Preparation of base metals by coupled reduction with platinum group metals. Very pure metals of the alkaline- earth, lanthanide and actinide series can be prepared from their oxides (or fluorides) through coupled reduction by pure hydrogen in presence of platinum group metals. According to a precursory paper on this subject (Berndt et al. 1974), the preparation scheme of Li, Ca, Sr, Ba, Am and Cf was described. As an example, Ca can be obtained by synthesis of a Pt compound, followed by its vacuum decomposition and recovery by distillation of the more volatile base metal ... 

AH the isotopes of americium belonging to the transuranic subseries of the actinide series are radioactive and are artificially produced. Americium has similar chemical and physical characteristics and is hofflologous to europium, located just above it in the rare-earth (lanthanide) series on the periodic table. It is a bright-white malleable heavy metal that is somewhat similar to lead. Americiums melting point is 1,176°C, its boiling point is 2,607°C, and its density is 13.68g/cm. ... 

After the discovery of plutoninm and before elements 95 and 96 were discovered, their existence and properties were predicted. Additionally, chemical and physical properties were predicted to be homologous (similar) to europium (gjEu) and gadolinium ( Gd), located in the rare-earth lanthanide series just above americium (gjAm) and curium ((,jCm) on the periodic table. Once discovered, it was determined that curium is a silvery-white, heavy metal that is chemically more reactive than americium with properties similar to uranium and plutonium. Its melting point is 1,345°C, its boihng point is 1,300°C, and its density is 13.51g/cm. ... 

Californium is a transuranic element of the actinide series that is homologous with dysprosium (gjDy), just above it in the rare-earth lanthanide series. Cf-245 was the first isotope of californium that was artificially produced. It has a half-life of just 44 minutes. Isotopes of californium are made by subjecting berkelium to high-energy neutrons within nuclear reactors, as follows + (neutrons and A, gamma rays) — °Bk — °Cf + (3- (beta particle... 

Symbol Nd atomic number 60 atomic weight 144.24 a rare earth lanthanide element a hght rare earth metal of cerium group an inner transition metal characterized by partially filled 4/ subshell electron configuration [Xe]4/35di6s2 most common valence state -i-3 other oxidation state +2 standard electrode potential, Nd + -i- 3e -2.323 V atomic radius 1.821 A (for CN 12) ionic radius, Nd + 0.995A atomic volume 20.60 cc/mol ionization potential 6.31 eV seven stable isotopes Nd-142 (27.13%), Nd-143 (12.20%), Nd-144 (23.87%), Nd-145 (8.29%), Nd-146 (17.18%), Nd-148 (5.72%), Nd-150 (5.60%) twenty-three radioisotopes are known in the mass range 127-141, 147, 149, 151-156. 

Rare earths - [LANTHANIDES] (Vol 14) -ocean raw material [OCEAN RAW MATERIALS] (Vol 17)... 

The lanthanide elements were once known as the rare earths. Lanthanides, however, are not particularly rare. Holmium, one of the less common lanthanides, is still 20 times more abundant than silver on Earth. The rare earth name comes instead from how difficult it was for early chemists to separate all of the lanthanides from one another. Because these elements add electrons to an inner shell, they all show the same face to other elements. This makes them all react very similarly with other elements, and it can be tricky to tell them apart. 

Paris by the French scientist Paul-Emile Lecoq de Boisbaudran. Its isolation was made possible by the development of ion-exchange separation in the 1950s. Dysprosium belongs to a series of elements called rare earths, lanthanides, or 4f elements. The occurrence of dysprosium is low 4.5 ppm (parts per million), that is, 4.5 grams per metric ton in Earth s crust, and 2 x 10 7 ppm in seawater. Two minerals that contain many of the rare earth elements (including dysprosium) are commercially important mon-azite (found in Australia, Brazil, India, Malaysia, and South Africa) and bast-nasite (found in China and the United States). As a metal, dysprosium is reactive and yields easily oxides or salts of its triply oxidized form (Dy3+ ion). 

In the sixth period, the filling of the Af orbitals (and the generation of the -block elements) begins as the rare-earth (lanthanide) elements from lanthanum to ytterbium are reached. The configurations determined from calculations and experiment can be recalled as needed by assuming that the orbitals are filled in the sequence Is— 2s—— 3s— 3p— 4s — 3d— Ap— Ss— Ad— Sp— hs— Af—ySd— Gp— Is Sf Gd. The energies of the 4f, 5d, and 6s orbitals are comparable over much of the sixth period, and thus their order of filling is erratic. 

Solution and Solid State NMR Studies of Alginic Acid Binding with Alkaline Earth, Lanthanide, and Yttrium Metal Ions... 

Through our studies of alkaline earth, lanthanide, and yttrium ions, and their interaction with the polyuronide al c acid, we would like to predict the environmental behavior of the actinides. We chose to begin our study by investigating the interaction of soil constituents with the divalent alkaline earth metal ions and the trivalent lanthanides, which serve as convenient trivalent actinide analogs. Soil is primarily composed of polyelectrolytes. By choosing a simple polyelectrolyte such as the polyuronide alginic acid, we can begin to establish possible pathways of metal ion transport. 

By examining the effect of alkaline earth, lanthanide and yttrium metal ions on alginates, we can begin to understand how these metals interact with simple components of soil matter. After laying the groundwork with these studies, we can then predict possible mechanisms for ion transport in soils. 

Examples of fluorophores that are used as labels in fluo-roimmunoassay and their properties are listed in Table 9-3. Initially, background fluorescence from drugs, drug metabolites, and protein-bound substances, such as bilirubm, limited the utility of this technique. However, this problem has largely been overcome by the use of rare earth (lanthanide) chelates and background rejection (time-resolved)... 

Besides supported Au [39f,i,l,o], other catalysts claimed in Dow patents include Agj alkali (alkaline earths, lanthanides) over Ti-containing supports. These systems givea propene conversion lower than 1%, high PO selectivity (but lower than that achieved with Au-based systems) and a H 2O/PO ratio much higher than that obtained with Au-based systems [39c,d,h,m,nj. The co-presence of Au, however, remarkably reduces the H2O/PO ratio, thus increasing hydrogen efficiency [39g,kj. 

The shift reagents are ions in the rare earth (lanthanide series) coordinated to organic ligands, generally b-diketone complexes of Eu3+ and Pr3 +. More recent shift reagents are... 

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