Yttrium metal preparation

E. Morrice, J. E. Murphy and M. M. Wong, Preparation of Rare Earth and Yttrium Metals by... 

Storms (1971) studied the phase relationship at temperatures between 1027 and 1827°C over a wide composition range in the Y-C system using a combination of mass spectrometric and thermal analysis techniques. Samples were prepared by arc melting purified crystal bar yttrium metal and a spectroscopically pure graphite rod. 

His suspicion, of course, had antecedents. Heinrich Rose discovered earlier that yttrium chloride itself is not volatile, although it was thought to be so earlier. What appears volatile is the impurity beryllium chloride. This finding spoke in favour of yttrium not being a pure element as believed earlier. Rose was the first to prepare metallic yttrium by reducing yttrium chloride and yttrium fluoride with metallic sodium. It turned out later, however, that this yttrium metal was still largely contaminated. 

Following Davey s preparation of potassium and sodium in 1807 by the electrolysis of a fused salt, other active metals were investigated with this technique. Lanthanum and cerium were prepared by Hillebrand and Norton (1875) and later on, these and the other light lanthanide metals by Muthmann and Weiss (1904), Hirsch (1911), Kremers and Stevens (1923), Trombe (1936) and Gray (1952). In recent years this method was refined and extended to a few of the heavy lanthanide and yttrium metals by the US Bureau of Mines group headed by Henrie and Morrice (see Morrice and Knickerbocker 1961, Beaudry and Gschneidner 1978, for more details). 

Another approach, as described by Carlson and Schmidt (1%7), involved the preparation of yttrium metal by the Ca reduction of YCI3 in the presence of Mg. The Mg and Ca were removed from the Y by a vacuum heat treatment followed by arc melting the resultant Y sponge. In a similar process Schmidt and Carlson (1974) prepared scandium metal by reducing ScCh with Ca and/or Mg. The reduced metal was purified by arc melting or vacuum distillation. 

Carlson, O.N. and F.A. Schmidt, 1961a, Metallothermic preparation of yttrium metal, in Spedding, F.H. and A.H. Daane, eds. The Rare Earths, (John Wiley Sons, Inc., New York) p. 113. 

Nolting, H.J., C.R. Simmons, and J.J. Klingenberg, 1960, J. Inorg. Nucl. Chem. 14, 208. Yttrium prepared by lithium reduction of anhydrous yttrium chloride prepared from yttrium oxide claim 99.8% purity but, in fact, contained <2372 ppm impurity including 1700 ppm non-metallic. (500 kg load, 10 mm indenter). 

Lundin and Yamamoto formed their alloys from metals of select purity . Major impurities in their samarium were < 0.038 wt% O, 0.02 wt% Ca, 0.005 wt% each Ce, Nd, Pr, B, Si and Zn and 0.003 wt% Zr. Their yttrium metal contained 0.037 wt% O, 0.01 wt% each Er and Tb and 0.005 wt% each Ce, Ho, Tb, Pr, B and Si. Alloys were prepared at 10 at% intervals and melted in sealed tantalum crucibles. Three or more melting cycles, well above the melting temperature, were performed before the thermal analysis of each alloy was carried out. 

Calcium metal is an excellent reducing agent for production of the less common metals because of the large free energy of formation of its oxides and hahdes. The following metals have been prepared by the reduction of their oxides or fluorides with calcium hafnium (22), plutonium (23), scandium (24), thorium (25), tungsten (26), uranium (27,28), vanadium (29), yttrium (30), zirconium (22,31), and most of the rare-earth metals (32). 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

The alkoxides and aryloxides, particularly of yttrium have excited recent interest. This is because of their potential use in the production of electronic and ceramic materials,in particular high temperature superconductors, by the deposition of pure oxides (metallo-organic chemical vapour deposition, MOCVD). They are moisture sensitive but mostly polymeric and involatile and so attempts have been made to inhibit polymerization and produce the required volatility by using bulky alkoxide ligands. M(OR)3, R = 2,6-di-terr-butyl-4-methylphenoxide, are indeed 3-coordinate (pyramidal) monomers but still not sufficiently volatile. More success has been achieved with fluorinated alkoxides, prepared by reacting the parent alcohols with the metal tris-(bis-trimethylsilylamides) ... 

In 2003, Livinghouse et al. also reported that chelating bis(thiophosphonic amidates) complexes of lanthanide metals, such as yttrium or neodymium, were able to catalyse intramolecular alkene hydroaminations. These complexes were prepared by attachment of the appropriate ligands to the metals by direct metalation with Ln[N(TMS)2]3- When applied to the cyclisation of 2-amino-5-hexene, these catalysts led to the formation of the corresponding pyrrolidine as a mixture of two diastereomers in almost quantitative yields and diastereos-electivities of up to 88% de (Scheme 10.81). 

Ferenc, W. et al., Monatsh. Chem., 1987, 118, 1087-1100 Preparation of the 2-nitrobenzoate salts of yttrium and the lanthanide metals (except praseodymium) as mono- or di-hydrates was studied. All melted and decomposed explosively above 250°C. 

DAS has rivb° 1.6156 and d25° 1.3992 the nuclear magnetic resonance spectrum has a singlet at 8.83 r and an A2B2 pattern at 2.62 r. Although DAS is very oxygen-sensitive, it is readily stored in sample bottles with serum caps. Complexes of many metals have been prepared exceptions include scandium, yttrium, lanthanum, and zinc. 

Recently, rare-earth metal complexes have attracted considerable attention as initiators for the preparation of PLA via ROP of lactides, and promising results were reported in most cases [94—100]. Group 3 members (e.g. scandium, yttrium) and lanthanides such as lutetium, ytterbium, and samarium have been frequently used to develop catalysts for the ROP of lactide. The principal objectives of applying rare-earth complexes as initiators for the preparation of PLAs were to investigate (1) how the spectator ligands would affect the polymerization dynamics (i.e., reaction kinetics, polymer composition, etc.), and (2) the relative catalytic efficiency of lanthanide(II) and (III) towards ROPs. 

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