Yttrium physical properties

The element yttrium (jjY), located just above lanthanum in group 3, is sometimes included in this series because its physical properties and chemical characteristics are similar to those of other elements in the series. 

It is possible to include yttrium among the rare earths, because of its properties, which are rather like those of some of the rare earths. For instance, when we express a physical property of the sulfides as a function of the ionic radii of the metals, the yttrium sulfide normally lies among the rare earth series, without any discontinuity, between dysprosium and erbium sulfides. 

Since the Ms hydrides may have interesting chemical and physical properties in addition to their remarkable structure, it was desirable to have a high-yield synthesis of these species. Investigation of the reactivity of the yttrium complexes [(CsH5)2Y(/i-H)(thf)]2 with a variety of lithium reagents has led to a synthesis of [(CsHs)2YH]3H Li(thf)4 in 75% yield according to Eq. (19) (56). 

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 elements with atomic numbers from 57 (l thanum) to 71 (lutetium) are referred to as the lanthanide elements. These elements and two others, scandium and yttrium, exhibit chemical and physical properties very similar to lanthanum. They are known as the rare earth elements or rare earths (RE). Such similarity of the RE elements is due to the configuration of their outer electron shells. It is well known that the chemical and physical properties of an element depend primarily on the structure of its outermost electron shells. For RE elements with increasing atomic number, the first electron orbit beyond the closed [Xe] shell (65 remains essentially in place while electrons are added to the inner 4f orbital. Such disposition of electrons about the nucleus of the rare earth atoms is responsible for the small effect an atomic number increase from 57 to 71 has on the physical and chemical properties of the rare earths. Their assignment to the 4f orbital leads to slow contraction of rare earth size with increasing atomic number. The 4f orbitals of both europium and gadolinium are half occupied [Xe] (4F6s and [Xe] (4F5d 6s, so that there... 

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. 

The syntheses, physical properties, and molecular structures of alkoxides and aryloxides have been discussed in CCC (1987).161 The alkoxides of scandium and yttrium were reviewed in CCC (1987).1 There have been more recent developments in this area and the impetus for this chemistry has been the developments in materials research. Metal alkoxides and /3-diketonates can be used as precursors for oxide and nonoxide thin films.162 The stable M—O bond and the volatility of the metal alkoxides are important features of this area of chemistry. This has lead to more research in this area particularly in synthesis, NMR, and X-ray crystallography. 

A recently introduced detector, yttrium-activated lutetium oxyorthosilicate (LYSO), has the physical properties similar to LSO and has been used in PET scanners by a commercial vendor. 

Andrew F and Salvador P (2002) Synthesis, structure and physical properties of yttrium-doped strontium manganese oxide films. Ceramics Sci 57 76-77. 

Physical Properties and Phase Identification in Yttrium—Alkaline Earth—Bismuth—Copper Oxide Systems... 

Russian investigators (Samsonov et al. 1961) prepared yttrium monocarbide by heating a mixture of the stoichiometric composition at 1900°C and measured the physical properties of this yttrium carbide (melting point at 1950 20°C). However, no structural data were given. 

Electronic Structures. Almost all the physical properties and chemical behavior of the rare earth elements find a logical explanation in terms of their electronic structures. Scandium, yttrium, lanthanum, and actinium are the first members, respectively, of the first, second, third, and fourth transition sequences of elements. In other words, each such element marks the beginning of an inner building where a stable group of 8 electrons is expanding to a completed (or more nearly complete) group of IS. This situation is illustrated for the first transition sequence. 

THE RARE EARTH elements are those from atomic numbers 57 (lanthanum) to 71 (lutetium) inclusive and elements 21 (scandium) and 39 (yttrium). They represent the largest group of chemically similar elements, but their physical properties differ markedly due to subtle features of electronic structure. Because of the similarity between... 

Since scandium is one of the nomnagnetic elements among the rare-earth series one might expect that the physical properties of compounds with scandium and the other nonmagnetic rare-earth elements (Y, La or Lu) are the same or at least very similar. This supposition is true in principle, however because of the much smaller atomic size of scandium compared with yttrium and also lutetium a deviating physical behaviour of the corresponding scandium compounds is frequently observable. 

The main focus of research on the rare earth silicates has been their preparation and structure. A summary of the structural data available is presented in table 14. In many cases the physical properties are unknown. An important application of the rare earth silicates is the use of yttrium oxyorthosilicate activated with terbium as a luminescent material in fluorescent lamps. Several patents have been published in this field. 

Kharchenko, O.I., 1977, Investigation of the ternary systems of yttrium, cerium and lanthanum with iron, cobalt, nickel and copper phase equilibria, crystal structures and some physical properties of the alloys, Ph.D. Chemistry thesis, 1977, Lvov (Lvov State University, Lvov) pp. 1-20. 

Weaver, J., C. Krafka, D. Lynch, and E. Koch, 1981b. Physics Data Optical Properties of Metals, Pt. II Noble Metals, Aluminum, Scandium, Yttrium, the Lanthanides and the Actinides, Fach-Informations-Zentrum, Karlsruhe. 

---