Neodymium physical properties

These same researchers also explored the efficacy of the individual rare earths as nodulizers (17). They concluded, by their ability to produce nodular iron having adequate physical properties without excessive iron carbides present, that cerium was the most effective of the four rare earth elements (lanthanum-neodymium) evaluated as nodulizers. They reported that it required 1.5 times as much neodymiun or praseodymium and three times as much lanthanum as cerium to yield equivalent results. 

Fluorescent and Physical Properties of Neodymium-Doped Alkali Silicate and Germanate Glasses... 

Other important physical properties of neodymium are given under Rare-Earth Elements and Metals. 

Lanthanide elements (referred to as Ln) have atomic numbers that range from 57 to 71. They are lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). With the inclusion of scandium (Sc) and yttrium (Y), which are in the same subgroup, this total of 17 elements are referred to as the rare earth elements (RE). They are similar in some aspects but very different in many others. Based on the electronic configuration of the rare earth elements, in this chapter we will discuss the lanthanide contraction phenomenon and the consequential effects on the chemical and physical properties of these elements. The coordination chemistry of lanthanide complexes containing small inorganic ligands is also briefly introduced here [1-5]. 

The materials derived from YBa2Cu307 by replacing yttrium with other rare earth elements (lutetium, ytterbium, thulium, erbium, hohnium, dysprosium, gadolinium, europium, samarium, neodymium, lanthanum) are also superconductors, with r, s of 88 to 96 K. The crystal structures of RBa2Cu307 are almost the same as those of YBa2Cu307. The lattice constant is slightly different for the different ionic radii of the rare earth elements, and yet their chemical and physical properties are almost the same as those of YBa2Cu307. 

Chatterjee and Taylor (1972) examined physical properties associated with different crystal structures in the neodymium-dysprosium alloy system. The purity of their starting metals was not reported. Alloys were prepared by arc melting the... 

RARE-EARTH ELEMENTS AND METALS. Sometimes referred to as the fraternal fifteen," because of similarities in physical and chemical properties, the rare-earth elements actually are not so rare. This is attested by Fig. 1, which shows a dry lake bed in California that alone contains well in excess of one million pounds of two of die elements, neodymium and praseodymium. The world s largest rare earth body and mine near Baotou, Inner Mongolia, China is shown in Fig. 2. It contains 25 million tons of rare earth oxides (about one quarter of the world s human reserves. The term rare arises from the fact that these elements were discovered in scarce materials. The term earth stems from die tact that the elements were first isolated from their ores in the chemical form of oxides and that the old chemical terminology for oxide is earth. The rare-earth elements, also termed Lanthanides, are similar in that they share a valence of 3 and are treated as a separate side branch of the periodic table, much like die Actinides. See also Actinide Contraction Chemical Elements Lanthanide Series and Periodic Table of the Elements. 

Despite Brauner s belief in the validity of the Mendeleev methodology, he also had to admit that he had not yet succeeded in resolving the rare-earth crisis. Thus Brauner wrote in 1901 with reference to praseodymium that its maximum valency was tetravalent, like that of cerium but that no place had been found in the periodic table for an element possessing the physical and chemical properties of praseodymium and its compounds (Brauner, 1901b). He also admitted that the difficulties of finding a place for neodymium in the periodic table were even greater than in the case of praseodymium. 

The lanthanide series of metals includes the 15 elements with atomic numbers 57-71, plus yttrium (atomic number 39). The lanthanides occur in the earth s crust at concentrations exceeding some commonly used industrial elements making the term rare earths something of a misnomer. For example, yttrium, cerium, lanthanum, and neodymium are present in the earth s crust at higher concentrations than lead. Of the 15 lanthanides, only promethium does not occur in nature - it is a man-made element. All of the lanthanides have similar physical and chemical properties. Because of similarities in their chemistry and toxicity, the characteristics of the lanthanides are often described as a group. Within the lanthanide group, however, there are differences between the toxicity of the individual lanthanide elements and their compounds. 

Neodymium. Neodymium can be present in relatively high concentrations in fluorapatites. Gaft et al. (2001a) lists Nd analyses for several natural apatites that are higher than any other REE except Ce, and at a concentration level of about 40% of the Ce value. Nd emission is well into the IR, and it is not sensitized by most of the other REE. Hence, Nd emission is expected to be relatively independent of other impurities, and will not contribute to visible luminescence. However, Nd -doped synthetic apatites are excellent laser materials, due to several physical attributes of the Nd electronic structure in the host lattice. Detailed evaluation of the optical properties of Nd in Ba fluorapatite... 

Owing to peculiar physical and chemical properties, rare-earth elements are used in various materials and consumer products, and thus, have become indispensable for our modem life. The world-wide rare-earth oxide consumption by the market sector in 2008 (Goonan, 2011) shown in Fig. 1 indicates that rare earths are used in glass industry, catalysts, neodymium magnets, battery alloys and other metallurgical additives, phosphors, ceramics, and other. According to the world mine production of rare earth in 2009 (Cordier, 2011),... 

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