Yttrium occurrence

For organometailic compounds, the situation becomes even more complicated because the presence of elements such as platinum, iron, and copper introduces more complex isotopic patterns. In a very general sense, for inorganic chemistry, as atomic number increases, the number of isotopes occurring naturally for any one element can increase considerably. An element of small atomic number, lithium, has only two natural isotopes, but tin has ten, xenon has nine, and mercury has seven isotopes. This general phenomenon should be approached with caution because, for example, yttrium of atomic mass 89 is monoisotopic, and iridium has just two natural isotopes at masses 191 and 193. Nevertheless, the occurrence and variation in patterns of multi-isotopic elements often make their mass spectrometric identification easy, as depicted for the cases of dimethylmercury and dimethylplatinum in Figure 47.4. 

R, C. Vickery, Scandium, yttrium and lanthanum, Chap, 31 in Comprehensive Inorganic Chemistry, Vol. 3, pp, 329-53, Pergamon Press, Oxford, 1973, and references therein, C. T. Horovitz (ed.), Scandium Its Occurrence, Chemistry, Physics, Metallurgy, Biology and Techndlogy, Academic Press, London, 1975, 598 pp. 

Assigning oxidation states of —2 to oxygen, + 3 to yttrium and + 2 to barium, one would obtain an oxidation state 7/3 for copper when jc = 0. The non-integer oxidation state of copper is interpreted as if 2/3 of the ions are present as Cu2+ and 1/3 as Cu3 +. This mixed-valent composition seems to be determinant for the occurrence of superconductivity. In fact, as noted in Table 1, all the superconducting ceramic oxides contain Cu in a non-stoichiometric composition. 

In addition, there exist a multitude of different applications in water analysis by ICP-MS for environmental control. For example, Lawrence et cdP determined rare earth element concentrations in natural waters (these are river, lake, sea or groundwater) by quadrupole ICP-MS using external calibration and employed river water reference material SLRS-4 to validate the analytical data. The speciation of yttrium and lanthanides in water samples by SEC-ICP-MS was studied by Haraguchi et a/.18 whereby the detection of La, Ce and Pr corresponded to the occurrence of large organic molecules. 

Jhe distribution of beryllium, boron, titanium, vanadium, chromium, cobalt, nickel, copper, zinc, gallium, germanium, tin, molybdenum, yttrium, and lanthanum in the principal coal-producing beds of the Interior Province has been studied by the U. S. Geological Survey. Data, methods of sampling, and analyses are discussed by Zubovic and others (II, 12). This chapter discusses the occurrence of 13 of these elements with respect to geological and geochemical environments of coal deposition and chemical properties of the elements. Zinc and tin are not included in this study because they were detected in only a few samples. 

Fluorite is a ubiquitous mineral and is so widespread in ils occurrence that only the most noteworthy can be mentioned. The English localities at Cumberland. Durham, and Weardale are world famous. Exceptionally heauiiful handed material of hlue fibrous character fruin Derbyshire, known as Blue-John, has been much-used for decorative curved pieces, such as vases and other ornamental objects. Norway has produced exceptional specimens from the famous Kongshcrg silver veins, as well as yttrium-rich fluorite from northern Norway associated with rare-earth minerals. Fine material has been obtained from the Transvaal in the Republic of South Africa, Tasmania and Australia. Large quantities of fluorite are mined in Mexico at Guadalcazar and Guanajuato. 

The lanthanides (Ln) include lanthanum (La) and the following fourteen elements—Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu— in which the 4f orbitals are progressively filled. These fifteen elements together with scandium (Sc) and yttrium (Y) are termed the rare-earth metals. The designation of rare earths arises from the fact that these elements were first found in rare minerals and were isolated as oxides (called earths in the early literature). In fact, their occurrence in nature is quite abundant, especially in China, as reserves have been estimated to exceed 84 x 106 tons. In a broader sense, even the actinides (the 5f elements) are sometimes included in the rare-earth family. 

Deuber R, Heim T (1991) Yttrium. In Merian E (ed) Metals and their compounds in the environment. Occurrence, analysis and biological relevance. VCH, Weinheim/New York/Basel/ Cambridge, pp 1299-1308... 

Xenotime, the orthophosphate of the yttrium-group rare earths, contains yttrium-group oxides (54 to 67 per cent) and cerium-group oxides (1 to 11 per cent), together with silica, thoria, zirconia, etc. It is neither as abundant nor as widespread in its occurrence as monazite, but has been reported from Norway, Sweden, Brazil, Colorado, North Carolina, and a few other localities. 

Occurrence Yttrium is a rare earth element and occurs in nearly all of the rare earth minerals. Rare earths are defined as a group of 17 elements, comprised of scandium, yttrium, and the lanthanides. The similar radii and oxidation states of the rare earths allows liberal substitution of the rare earths for one another into the crystal lattice sites of minerals. This substimtion accounts for their wide dispersion in the earth s crust and the characteristic occurrence as a group of elements within more than 100 minerals. The principal ores of the rare earths are basmasite, monazite, and xenotime. Several of the ores occur in unique geologic settings, whereas others are found in similar occurrences worldwide. 

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